Buick Encore: Diagnostic information and procedures

SCHEMATIC WIRING DIAGRAMS

HVAC WIRING SCHEMATICS (ENCORE)

Power, Ground, and Blower Motor

Fig. 1: Power, Ground, and Blower Motor

Compressor Controls

Fig. 2: Compressor Controls

Duct and Evaporator Temperature Sensors

Fig. 3: Duct and Evaporator Temperature Sensors

Mode and Temperature Control Actuators

Fig. 4: Mode and Temperature Control Actuators

Sunload Sensor and Windshield Temperature Sensor

Fig. 5: Sunload Sensor and Windshield Temperature Sensor

DIAGNOSTIC INFORMATION AND PROCEDURES

HVAC COMPONENT REPLACEMENT REFERENCE

HVAC Component Replacement Reference

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

DTC B0163, B0183, OR B1405: Passenger compartment temperature sensor/solar load sensor/control module voltage reference

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0163

Passenger Compartment Temperature Sensor Circuit

DTC B0183

Solar Load Sensor Circuit

DTC B1405

Control Module Voltage Reference Output 2 Circuit

For symptom byte information, refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

The ambient light/sunload sensor integrates the sunload and passenger compartment temperature functions within a single assembly.

The solar sensor uses 4 unique circuits as detailed below:

• Low reference circuit - This is a common ground for the ambient light/sunload sensor assembly.
• Temperature signal circuit - This is the signal circuit for the temperature sensor.
• Clock signal circuit - This has 2 functions, via a high side PWM signal, the HVAC control module supplies power to the sensor as well as a clock input for the sensor microprocessor.
• Sunload signal circuit - This is used as an output from the solar sensor to the HVAC control module to transmit sun heat (IR) intensity, elevation, and azimuth data.

The passenger compartment temperature sensor is a negative temperature coefficient thermistor. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The automatic HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

• Ignition ON
• The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02

The input signal is out of range. The HVAC control module detects voltage less than 0.1 V on the temperature signal circuit.

B0163 05

The input signal is out of range. The HVAC control module detects voltage less than 0.1 V on the temperature signal circuit.

B0163 05

The input signal is out of range. The HVAC control module detects voltage greater than 4.9 V on the temperature signal circuit.

B0183 02

The input signal is out of range. The HVAC control module detects voltage less than 0.1 V on the solar sensor signal circuit.

B0183 05

The input signal is out of range. The HVAC control module detects voltage greater than 4.9 V on the solar sensor signal circuit.

B1405 02

The input signal is out of range. The HVAC control module detects voltage less than 10 V on the clock/power supply circuit.

B1405 05

The input signal is out of range. The HVAC control module detects a short to voltage or an open the clock/power supply circuit.

Action Taken When the DTC Sets

B0163 02, B0163 05, B0183 02, B0183 05

The system will use the last valid values as a default.

B1405 02, B1405 05

If no value is read at the time of fault, the HVAC control module uses 0 W/m2 as intensity.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify DTCs B0163 and B0183 are not both set concurrently.

If both DTCs are set

Refer to Low Reference Test.

1. If both DTCs are not set
2. Verify DTC B0163, B0183, or B1405 is not set.

If one of the DTCs is set

Refer to the appropriate diagnostic in Circuit/System Testing.

If none of the DTCs are set

3. Verify the B10B Ambient Light/Sunload Sensor is accurate.

If the sensor is not accurate

1. Perform the following Circuit/System Testing in the order listed below:

• Circuit/System Testing - Low Reference Test
• Circuit/System Testing - DTC B0163
• Circuit/System Testing - DTC B1405
• Circuit/System Testing - DTC B0183

If the sensor is accurate

4. All OK.

Circuit/System Testing

Low Reference Test

NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground.

1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If less than 10 ohms

3. Test or replace the B10B Ambient Light/Sunload Sensor.

DTC B0163

NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor, ignition ON.
2. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is less than -37ºC (- 35ºF).

If -37ºC (-35ºF) or greater

1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
2. Test for infinite resistance between the signal circuit terminal 3 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC Control Module.

If less than -37ºC (-35ºF)

3. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.
4. Verify the scan tool parameter Passenger Compartment Air Temperature (Unfiltered) parameter is greater than 78ºC (172ºF).

If 78ºC (172ºF) or less

1. Ignition OFF, remove the jumper wire and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Ignition OFF.
4. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If greater than 78ºC (172ºF)

5. Test or replace the B10B Ambient Light/Sunload Sensor.

DTC B0183

NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor, ignition ON.
2. Test for 4.8-5.2 V between the signal circuit terminal 4 and ground.

If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
2. Test for infinite resistance between the signal circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If greater than for 5.2 V

1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K33 HVAC Control Module.

If between 4.8-5.2 V

3. Test or replace the B10B Ambient Light/Sunload Sensor.
4. Verify DTC B0183 did not reset.

If DTC B0183 reset

Replace the K33 HVAC Control Module.

If DTC B0183 did not reset

5. All OK.

DTC B1405

NOTE: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor, ignition ON.
2. Test for greater than 10 V between signal circuit terminal 2 and ground.

If less than 10 V

1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
2. Test for infinite resistance between signal circuit terminal 2 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If 10 V or greater

3. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
4. Test for less than 1 V between the signal circuit terminal 2 and ground.

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

5. Test or replace the B10B Ambient Light/Sunload Sensor.
6. Verify DTC B1405 did not reset.

If DTC B1405 reset

Replace the K33 HVAC Control Module.

If DTC B1405 did not reset

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

DTC B0173, B0178, B0509, B0514 OR B3933: DUCT AIR TEMPERATURE SENSOR/EVAPORATOR TEMPERATURE SENSOR

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0173 02

Upper Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0173 05

Upper Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0178 02

Lower Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0178 05

Lower Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0509 02

Upper Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0509 05

Upper Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0514 02

Lower Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0514 05

Lower Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B3933 02

Air Conditioning Evaporator Temperature Sensor Circuit Short to Ground

DTC B3933 05

Air Conditioning Evaporator Temperature Sensor Circuit High Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The air temperature sensors are a 2-wire negative temperature coefficient thermistor. The vehicle uses the following air temperature sensors:

• Air temperature sensor - left upper
• Air temperature sensor - left lower
• Air temperature sensor - right upper
• Air temperature sensor - right lower
• A/C evaporator temperature sensor

This sensor operates using signal and low reference circuits. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor sends a signal voltage between 0-5 V. If the HVAC control module detects a malfunctioning sensor the software uses a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

Conditions for Running the DTC

• Ignition ON.
• The HVAC control module is ON.

Conditions for Setting the DTC

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

The sensor signal is within specified range between 0.1-4.9 V.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify DTC B3933 is not set.

If DTC B3933 is set

Refer to Circuit/System Testing - Without Scan Tool Support.

If DTC B3933 is not set

3. Verify the appropriate temperature sensor has a parameter displayed in HVAC scan tool information.

If there is no scan tool parameter

Refer to Circuit/System Testing - Without Scan Tool Support.

If there is a scan tool parameter

4. Refer to Circuit/System Testing - With Scan Tool Support

Circuit/System Testing

With Scan Tool Support

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 ohms between the low reference circuit terminal B and ground.

If 10 ohms or greater

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If less than 10 ohms

3. Ignition ON.
4. Verify the appropriate scan tool temperature sensor parameter is less than -37ºC (-35ºF)

If greater than -37ºC (-35ºF)

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for infinite resistance between the signal circuit terminal A and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC Control Module.

If -37ºC (-35ºF) or less

5. Install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B.
6. Verify the scan tool temperature sensor parameter is greater than 77ºC (170ºF).

If less than 77ºC (170ºF)

1. Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Ignition OFF
4. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If 77ºC (170ºF) or greater

7. Test or replace the temperature sensor.

Without Scan Tool Support

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test

2. Test for less than 10 ohms between the low reference circuit terminal B and ground.

If 10 ohms or greater

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If less than 10 ohms

3. Test for 4.8-5.2 V between the signal circuit terminal A and ground.

If less than 4.8 V

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for infinite resistance between the signal circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If greater than 5.2 V

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K33 HVAC Control Module.

If between 4.8-5.2 V

4. Test or replace the temperature sensor.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
6. Verify the DTC does not set.

If the DTC sets

Replace the K33 HVAC Control Module.

If the DTC does not set

7. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

DTC B018A, B048C, B048F, OR B1395: Windshield temperature sensor/humidity sensor/control module voltage reference

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B018A

Windshield Temperature Sensor Circuit

DTC B048C

Humidity Sensor Humidity Circuit

DTC B048F

Humidity Sensor Temperature Circuit

DTC B1395

Control Module Voltage Reference Output Circuit

For symptom byte information, refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor all in one assembly.

This sensor assembly provides information about:

• Relative humidity level at the windshield inside the vehicle
• Temperature of the windshield inside the vehicle
• Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor usage to a minimum without causing any fog.

The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield.

The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient.

Conditions for Running the DTC

• Ignition ON.
• The HVAC control module is ON.

Conditions for Setting the DTC

B018A 02, B048C 02, or B048F 02

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048F 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

B1395 03

The HVAC control module detects the 5 V reference voltage out of range. The 5 V reference voltage is less than 4.5 V for more than 50 ms.

B1395 07

The HVAC control module detects the 5 V reference voltage out of range. The 5 V reference voltage is greater than 5.5 V for more than 50 ms.

Action Taken When the DTC Sets

• The system will use the last valid values as default.
• If no value is read at the time of fault, the HVAC control module uses 60% for humidity.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B160 Windshield Temperature and Inside Moisture Sensor. It may take up to 10 min for all vehicle systems to power down

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 ohms between the low reference circuit terminal 3 and ground.

If 10 ohms or greater

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If less than 10 ohms

3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.

If less than 4.8 V

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the 5 V reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If greater than 5.2 V

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K33 HVAC Control Module.

If between 4.8-5.2 V

5. Verify the scan tool parameters listed below are less than -37ºC (-35ºF).

• Windshield Temperature
• Passenger Compartment Humidity Sensor Temperature

If -37ºC (-35ºF) or greater

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
2. Test for infinite resistance between the signal circuit terminals listed below and ground:

• Windshield temperature sensor signal terminal 4
• Passenger compartment humidity sensor temperature signal terminal 5

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC Control Module.

If less than -37ºC (-35ºF)

6. Install a 3 A fused jumper wire between the low reference circuit terminal 3 and each signal circuit terminal listed below:

• Windshield temperature sensor signal terminal 4
• Passenger compartment humidity sensor temperature signal terminal 5

7. Verify the appropriate scan tool parameter listed below is greater than 114ºC (238ºF).

• Windshield Temperature
• Passenger Compartment Humidity Sensor Temperature

If 114ºC (238ºF) or less

1. Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminals listed below and ground:

• Windshield temperature sensor signal terminal 4
• Passenger compartment humidity sensor temperature signal terminal 5

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If greater than 114ºC (238ºF)

8. Remove the jumper wire.
9. Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%.

If 95% or less

1. Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for infinite resistance between the signal circuit terminal 2 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC Control Module.

If greater than 95%

10. Install a 3 A fused jumper wire between the passenger compartment humidity signal circuit terminal 2 and the low reference circuit terminal 3.
11. Verify the scan tool Passenger Compartment Humidity Sensor parameter is less than 5%.

If 5% or greater

1. Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 2 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If less than 5%

12. Test or replace the B160 Windshield Temperature and Inside Moisture Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

DTC B0193: Front blower motor speed circuit

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0193 01

Front Blower Motor Speed Circuit Short to Battery

DTC B0193 06

Front Blower Motor Speed Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit/System Description

The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor control module has 4 circuits: a B+ input, a signal input from the HVAC control module, a B+ output to the blower motor, and a low side pulse width modulation (PWM) output. The HVAC control module provides a low side (PWM) signal to the blower motor control module in order to request the blower motor speed. The blower motor control module grounds the blower motor using a low side PWM signal in order to vary the blower motor speed.

Conditions for Running the DTC

• Ignition ON.
• The HVAC control module is ON.

Conditions for Setting the DTC

B0193 01

The voltage at the HVAC control module output to the blower motor control module is always high.

B0193 06

The voltage at the HVAC control module output to the blower motor control module is always low or fluctuating.

Action Taken When the DTC Sets

The blower motor is inoperative

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

Inspect the motor shaft for rust or other foreign material which may prohibit proper motor operation.

If the motor operates properly please reinstall it and check for Preliminary Information or Technical Service Bulletins.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the K8 Blower Motor Control Module. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.

If 10 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 6 and ground.

If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF, remove the test lamp.
2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF, remove the test lamp.
2. Test for infinite resistance between the B+ circuit terminal 6 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Disconnect the X2 harness connector at the K8 Blower Motor Control Module and disconnect the harness connector at the M8 Blower Motor.
4. Test for infinite resistance between the M8 Blower Motor control circuit terminal B and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, test or replace the M8 Blower Motor.

If the test lamp illuminates

5. Remove the test lamp.
6. Test for 2.6-3.2 V between the control circuit terminal 3 and ground.

If less than 2.6 V

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance.

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms replace the K33 HVAC Control Module.

If greater than 3.2 V

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K33 HVAC Control Module.

If between 2.6-3.2 V

7. Ignition OFF, connect the X1 harness connector at the K8 Blower Motor Control Module and disconnect the harness connector at the M8 Blower Motor, ignition ON and blower ON.
8. Verify a test lamp illuminates between the control circuit terminal 1 and ground.

If the test lamp does not illuminate

1. Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
2. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms replace the K8 Blower Motor Control Module.

If the test lamp illuminates

9. Connect a test lamp between control circuit terminal 1 and control circuit terminal 2.
10. Verify the test lamp becomes progressively brighter as the blower speed is increased and progressively dimmer as the blower speed is decreased.

If the test lamp does not illuminate

1. Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module, ignition ON.
2. Test for less than 1 V between the control circuit terminal 1 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms replace the K8 Blower Motor Control Module.

If the test lamp illuminates, but does not change in brightness

1. Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K8 Blower Motor Control Module.

If the test lamp changes in brightness as the blower speed is changed

11. Test or replace the M8 Blower Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

DTC B0223, B022A, B0233, B023A, B0408, OR B0418: Recirculate position command/air flow control/temperature control circuit

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B0223 01

Recirculate Position Command 1 Circuit Short to Battery

DTC B0223 06

Recirculate Position Command 1 Circuit Low Voltage/Open

DTC B022A 01

Recirculate Position Command 2 Circuit Short to Battery

DTC B022A 06

Recirculate Position Command 2 Circuit Low Voltage/Open

DTC B0233 01

Air Flow Control Circuit Short to Battery

DTC B0233 06

Air Flow Control Circuit Low Voltage/Open

DTC B023A 02

HVAC Actuators Supply Voltage Short to Ground

DTC B0408 01

Main Temperature Control Circuit Short to Battery

DTC B0408 06

Main Temperature Control Circuit Low Voltage/Open

DTC B0418 01

Right Temperature Control Circuit Short to Battery

DTC B0418 06

Right Temperature Control Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit/System Description

Stepper motors are used for temperature regulation, air distribution control and recirculation door control.

With the switches and dials on the HVAC controls, air temperature door position, mode door position and recirculation door position can be selected. The selected values are passed to the HVAC control module via serial data. The HVAC control module supplies a 12 V control voltage to the stepper motors and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motors move the appropriate doors into the calculated positions, in order to reach the desired positions.

Conditions for Running the DTC

• Ignition ON.
• The HVAC control module is ON.

Conditions for Setting the DTC

B023A 02

The stepper motors supply output is shorted to ground.

B0223 01, B022A 01, B0233 01, B023A 01, B0408 01 or B0418 01

At least one control circuits of the appropriate stepper motor is shorted to voltage when motor starts moving.

Faults are not detected when motor is already running or target position is already reached.

B0223 06, B022A 06, B0233 06, B0233 06, B0408 06 or B0418 06

At least one control circuits of the appropriate stepper motor is shorted to ground or open when motor starts moving. Faults are not detected when motor is already running or target position is already reached.

Action Taken When the DTC Sets

B023A

• The affected output will be switched off for hardware protection.
• All stepper motors are deactivated.

B0223, B022A, B0233, B0408 or B0418,

• The affected output will be switched off for hardware protection.
• The affected stepper motor is deactivated.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Perform the Actuator Recalibration procedure.
2. Verify the concern or DTC has been corrected.

If the concern or DTC has not been corrected

1. Verify DTC B023A is not set.

• If DTC B023A is set

Refer to Circuit/System Testing - DTC B023A.

• If DTC B023A is not set

Refer to Circuit/System Testing - DTC B0223, B022A, B0233, B0408 or B0418.

If the concern or DTC has been corrected

3. All OK.

Circuit/System Testing

DTC B023A

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down.

• M37 Mode Door Actuator
• M46 Air Recirculation Door Actuator
• M6L Air Temperature Door Actuator - Left
• M6R Air Temperature Door Actuator - Right

2. Disconnect the X3 and X4 harness connectors at the K33 HVAC Control Module.
3. Test for infinite resistance between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

4. Ignition ON.
5. Test for less than 1 V between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

6. Connect the X3 and X4 harness connectors at the K33 HVAC Control Module, ignition ON.
7. Clear all DTCs.
8. Verify DTC B023A is not set.

If the DTC is set.

Replace the K33 HVAC Control Module.

If the DTC is not set.

9. Verify DTC B023A does not set after connecting each of the components listed below one at a time and operating them through their full range.

• M37 Mode Door Actuator
• M46 Air Recirculation Door Actuator
• M6L Air Temperature Door Actuator - Left
• M6R Air Temperature Door Actuator - Right

If the DTC sets

Replace the component that was connected immediately before the DTC set.

If the DTC does not set

10. All OK.

DTC B0223, B022A, B0233, B0408 or B0418

1. Ignition OFF, disconnect the harness connector at the appropriate door actuator, ignition ON.
2. Verify a test lamp flashes when connected between the 12 V reference circuit terminal 2 and ground.

If the test lamp does not flash

1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
2. Test for less than 2 ohms in the 12 V control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If the test lamp flashes

3. Connect a test lamp between each control circuit listed below and B+.

• Control Circuit - terminal 1
• Control Circuit - terminal 3
• Control Circuit - terminal 4
• Control Circuit - terminal 6

4. Command the appropriate door actuator in both directions.
5. Verify the test lamp turns ON and then OFF during at least one of the directional commands

If the test lamp is always ON

1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K33 HVAC Control Module.

If the test lamp is always OFF

1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Ignition OFF
4. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance is the circuit.
• If less than 2 ohms, replace the K33 HVAC Control Module.

If the test lamp turns ON and then OFF

6. Replace the door actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

DTC P0532 OR P0533: Air conditioning (a/c) refrigerant pressure sensor

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of the diagnostic category.

DTC Descriptors

DTC P0532

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

DTC P0533

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the ECM to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. The ECM may use this information to turn the cooling fans on as well as to monitor clutch engagement. The HVAC module will receive the A/C refrigerant pressure information from the ECM via serial data.

Conditions for Running the DTC

• Engine is running.
• Any of the conditions for setting the DTC are met for 15 s.
• Battery voltage is between 11-18 V.

Conditions for Setting the DTC

P0532

The ECM detects that the A/C pressure is less than 1 psi (0.25 V).

P0533

The ECM detects that the A/C pressure is more than 428 psi (4.92 V).

Action Taken When the DTC Sets

• The A/C compressor is disabled.
• The ECM will illuminate the malfunction indicator lamp (MIL).

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON
2. Verify the scan tool engine control module A/C High Side Pressure Sensor parameter is between 6.8 kPa (1 psi) and 2950 kPa (428 psi).

• If not between 6.8 kPa (1 psi) and 2950 kPa (428 psi)

Refer to Circuit/System Testing

If between 6.8 kPa (1 psi) and 2950 kPa (428 psi)

3. All OK

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B1 A/C Refrigerant Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 1 and ground.

If 10 ohms or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.

If less than 10 ohms

3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground.

If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the 5 V reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.

If greater than 5.2 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.

If between 4.8-5.2 V

5. Verify the scan tool A/C High Side Pressure Sensor parameter is less than .25 V.

If .25 V or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 3 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.

If less than .25 V

6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.
7. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.8 V.

If 4.8 V or less

1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit terminal 3 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.

If greater than 4.8 V

8. Test or replace the B1 A/C Refrigerant Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for engine control module replacement, programming and setup

DTC P0645, P0646, OR P0647: Air conditioning (A/C) compressor clutch relay

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0645

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit

DTC P0646

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit Low Voltage

DTC P0646

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit Low Voltage

DTC P0647

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit High Voltage

Diagnostic Fault Information

Circuit/System Description

When the A/C switch is pressed, the HVAC control module sends a serial data message to the engine control module (ECM) indicating the A/C request. In response to this message, the ECM grounds the A/C compressor clutch relay control circuit energizing the A/C compressor clutch relay. With the relay contacts closed, battery voltage is applied through the A/C compressor clutch control circuit activating the A/C compressor clutch

Conditions for Running the DTC

• The ignition voltage is between 11-18 volts.
• The engine speed is greater than 600 RPM.
• An A/C request is made.

Conditions for Setting the DTC

P0645 or P0646

The ECM detects a short to ground or an open at the A/C compressor clutch relay control circuit.

P0647

The ECM detects a short to voltage at the A/C compressor clutch relay control circuit.

Action Taken When the DTC Sets

P0645 or P0646

The A/C compressor is inoperative or always active

P0647

The A/C compressor is inoperative.

Conditions for Clearing the DTC

A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LUV) , Powertrain Diagnostic Trouble Code (DTC) Type Definitions (2H0)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, and all vehicle systems OFF. Disconnect the harness connector at the Q2 A/C Compressor Clutch. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the Q2 A/C Compressor Clutch ground circuit terminal A and ground.

If 10 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

3. Connect a test lamp between the control circuit terminal B and ground, ignition ON.
4. Verify the test lamp does not turn ON and OFF when commanding the Q2 A/C Compressor Clutch On and Off with a scan tool.

If the test lamp turns ON and OFF

Test or replace the Q2 A/C Compressor Clutch

If the test lamp does not turn ON and OFF

5. Ignition OFF, connect the harness connector at the Q2 A/C Compressor Clutch. Disconnect the X3 harness connector at the X50A Fuse Block - Underhood, ignition ON.
6. Verify the Q2 A/C Compressor Clutch is not activated.

If the Q2 A/C Compressor Clutch is activated

1. Ignition OFF, disconnect the harness connector at the Q2 A/C Compressor Clutch, ignition ON.
2. Test for less than 1 V between the control circuit terminal B and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, test or replace the Q2 A/C Compressor Clutch.

If the Q2 A/C Compressor Clutch is not activated

7. Connect a 10 A fused jumper wire between the control circuit terminal B5 and B+.
8. Verify the Q2 A/C Compressor Clutch activates.

If the Q2 A/C Compressor Clutch does not activate

1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the Q2 A/C Compressor Clutch, ignition ON.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the Q2 A/C Compressor Clutch.

If the Q2 A/C Compressor Clutch activates

9. Ignition OFF, connect the X3 harness connector at the X50A Fuse Block - Underhood and disconnect the harness connector at the K20 Engine Control Module, ignition ON.
10. Verify the Q2 A/C Compressor Clutch is not activated.

If the Q2 A/C Compressor Clutch is activated

1. Ignition OFF, disconnect the X3 harness connector at the X50A Fuse Block - Underhood.
2. Test for infinite resistance between the X3 X50A Fuse Block - Underhood control circuit terminal B4 and ground.

• If less than Infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, test or replace the X50A Fuse Block - Underhood.

If the Q2 A/C Compressor Clutch is not activated

11. Connect a 3 A fused jumper wire between the K20 Engine Control Module control circuit terminal for the KR29 A/C Compressor Clutch Relay and ground.
12. Verify the Q2 A/C Compressor Clutch activates.

If the Q2 A/C Compressor Clutch does not activate

1. Ignition OFF, remove the jumper wire, disconnect the X3 harness connector at the X50A Fuse Block - Underhood, ignition ON.
2. Test for less than 1 V between the X3 X50A Fuse Block - Underhood control circuit terminal B4 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the X50A Fuse Block - Underhood.

If the Q2 A/C Compressor Clutch activates

13. Replace the K20 Engine Control Module.

Component Testing

Compressor Clutch Test

1. Ignition OFF, disconnect the Q2 A/C Compressor Clutch.
2. Test for 3.9 - 4.3 ohms between terminals A and B

If not between 3.9 - 4.3 ohms

Replace the Q2 A/C Compressor Clutch.

If between 3.9 - 4.3 ohms

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Front Compartment Fuse Block Replacement
• Control Module References for engine control module replacement, programming and setup

Symptoms - HVAC systems - automatic

NOTE: The following steps must be completed before using the symptom tables:

1. Perform the Diagnostic System Check - Vehicle before using the HVAC System Malfunction procedure in order to verify that all of the following are true:

• There are no DTCs set.
• The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Automatic HVAC Description and Operation.

Visual/Physical Inspection

NOTE: Shutting one or more outlets may adversely affect the Automatic HVAC system by producing erroneous duct air temperature sensor readings in the duct connecting to the closed outlet. Where possible, always operate the Automatic HVAC system with all outlets open.

• Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories .
• Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
• Verify the A/C compressor turns freely and is not seized.
• Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
• The A/C compressor will not operate in cold outside air temperatures.
• The following conditions may cause window fogging:

• Wet carpet or mats
• High humidity
• Interior water leak
• Blocked A/C evaporator drain tube
• Maximum passenger capacity
• Blocked body pressure relief valves

• Inspect the air distribution system for causes of reduced air flow:

• Obstructed or dirty passenger compartment air filter, if equipped
• Blocked or damaged air inlet or outlet vents

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to HVAC System Malfunction in order to diagnose the symptom.

HVAC System malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Aids

Check the following mechanical fault sources:

• Air distribution box
• Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J43600 Air Conditioning Service Center

Circuit/System Verification

NOTE: Check for bulletins before proceeding.

1. Ignition ON.
2. Verify every applicable scan tool Switch parameter changes when pressing the appropriate switch on the A26 HVAC Controls.

If any parameter does not change

Replace the A26 HVAC Controls.

If all parameters change

3. Verify the blower motor operates properly with the blower motor switch in each speed position.

If the blower motor does not operate in each speed position

Refer to DTC B0193.

If the blower motor operates properly in each speed position

4. Verify the HVAC doors listed below move when pressing the appropriate switch.

• Driver Temperature
• Passenger Temperature
• Mode
• Recirculation

If any HVAC door does not move

Refer to DTC B0223, B022A, B0233, B023A, B0408, or B0418.

If all HVAC doors move

5. Install the J43600 Air Conditioning Service Center.
6. Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool ECM A/C High Side Pressure Sensor parameter

If the reading is not within 10%

Refer to DTC P0532 or P0533.

If the reading is within 10%

7. Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).

If the reading is not between 269-2929 kPa (39-425 PSI)

Refer to Air Conditioning (A/C) System Performance Test .

If the reading is between 269-2929 kPa (39-425 PSI)

8. Verify the scan tool parameters listed below are within 10% of ambient temperature.

• Lower Left Duct Air Temperature Sensor
• Upper Left Duct Air Temperature Sensor
• Lower Right Duct Air Temperature Sensor
• Upper Right Duct Air Temperature Sensor
• A/C Evaporator Temperature Sensor

If not within 10% of ambient temperature

Refer to DTC B0173, B0178, B0509, B0514 or B3933.

If within 10% of ambient temperature

9. Verify the scan tool parameters listed below are within 10% of actual conditions.

• Passenger Compartment Humidity
• Passenger Compartment Humidity Sensor Temperature
• Passenger Compartment Windshield Temperature

If not within 10% of actual conditions

Refer to DTC B018A, B048C, B048F, or B1395.

If within 10% of actual conditions

10. Engine ON, A/C system ON.
11. Verify cool air flows from the ducts with the temperature control in the coldest position.

If the air is not cool

1. Verify the Q2 A/C Compressor Clutch is engaged.

• If the Q2 A/C Compressor Clutch is not engaged, refer to Air Conditioning Compressor Malfunction.
• If the Q2 A/C Compressor Clutch is engaged, refer to Air Conditioning (A/C) System Performance Test .

If the air is cool

12. Verify warm air flows from the ducts with the temperature control in the warmest position.

If the air is not warm

Refer to Heating Performance Diagnostic .

If the air is warm

13. Engine OFF, ignition ON.
14. Verify the Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel and changes when shining a bright light on it.

If the Sunload parameter does not change

Refer to DTC B0163, B0183, or B1405.

If the Sunload parameter changes

15. Verify the actual inside air temperature, using a thermometer, is less than 3ºC (5ºF) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter.

If greater than a 3ºC (5ºF) difference

Refer to DTC B0163, B0183, or B1405.

If less than a 3ºC (5ºF) difference

16. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

Air conditioning compressor malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The A/C compressor uses a conventional belt driven magnetic clutch to engage and mechanically turn the compressor. When the A/C switch is pressed, the HVAC control module sends an A/C request message to the ECM via serial data. If specific criteria is met, the ECM then grounds the A/C compressor clutch relay control circuit, which will switch the A/C compressor clutch relay. With the relay contacts closed, battery voltage is supplied to the permanently grounded A/C compressor clutch. The A/C compressor clutch will then be activated.

Diagnostic Aids

The following conditions must be met in order to turn on the A/C compressor:

• Battery voltage is between 9-18 V.
• Engine coolant temperature is less than 124ºC (255ºF).
• Engine speed is greater than 600 RPM.
• Engine speed is less than 5 500 RPM.
• A/C high side pressure is between 269-2 929 kPa (39-425 PSI).
• Throttle position is less than 100%.
• Evaporator temperature is greater than 3ºC (38ºF).
• ECM does not detect excessive torque load.
• ECM does not detect insufficient idle quality.
• The ambient temperature is above 1ºC (34ºF).
• Blower motor ON

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - Encore

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Refer to HVAC System Malfunction before performing this procedure.

1. Ignition ON, press and release the A/C Switch.
2. Verify the HVAC control module scan tool A/C Switch parameter changes between Active and Inactive.

If the parameter does not change

Replace the A26 HVAC Controls.

If the parameter changes

3. Set A/C system to coolest setting with blower ON.
4. Press and release the A/C switch several times.
5. Verify the engine control module (ECM) scan tool A/C Request Signal parameter changes between Active and Inactive.

If the parameter does not change

Replace the K33 HVAC Control Module.

If the parameter changes

6. Verify the A/C compressor clutch engages when commanding the engine control module (ECM) A/C Relay output function On and Off with a scan tool.

If the A/C compressor clutch does not engage

Refer to DTC P0645, P0646, or P0647

If the A/C compressor clutch engages

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

Actuator recalibration

HVAC Control Module Replacement

When replacing or disconnecting the HVAC control module, it will be necessary to perform a recalibration process. When installing or reconnecting the HVAC control module, be sure to perform the following: Preferred Method (with Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

1. Ignition OFF.
2. Disconnect the scan tool.
3. Install/connect the HVAC control module.
4. Connect all previously disconnected components.
5. Start the vehicle.
6. With the scan tool, initiate the HVAC Actuators Learn feature of the HVAC control module Special Functions menu.
7. Operate system and verify that no DTCs have set as current DTCs.
8. If DTC B101E 4B is set after attempting the actuator recalibration procedure, perform the following:

1. Verify which actuator does not have a scan tool learn status parameter status of complete.
2. Verify the unlearned actuator is physically rotating - A common cause of DTC B101E 4B is an actuator that is electrically OK but fails to physically rotate (e.g. stripped gears).
3. If the unlearned actuator is not physically rotating, replace the actuator, otherwise replace the HVAC control module.

Alternate Method (without Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

1. Clear all DTCs.
2. Ignition OFF.
3. Install/connect the HVAC control module.
4. Connect all previously disconnected components.
5. Remove the HVAC control module fuse for a minimum of 10 s.
6. Install the HVAC control module fuse.
7. Start the vehicle.
8. Wait 40 s for the HVAC control module to self-calibrate.

Actuator Replacement

When replacing an HVAC actuator it will be necessary to allow the HVAC control module to perform a recalibration process. When installing an HVAC actuator be sure to perform one of the following: Preferred Method (with Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

1. Clear all DTCs.
2. Ignition OFF.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Start the vehicle.
6. With the scan tool, initiate the HVAC Actuators Relearn feature of the HVAC control module Special Functions menu.
7. Operate system and verify that no DTCs have set as current DTCs.
8. If DTC B101E 4B is set after attempting the actuator recalibration procedure, perform the following:

1. Verify which actuator does not have a scan tool learn status parameter status of complete.
2. Verify the unlearned actuator is physically rotating - A common cause of DTC B101E 4B is an actuator that is electrically OK but fails to physically rotate (e.g. stripped gears).
3. If the unlearned actuator is not physically rotating, replace the actuator, otherwise replace the HVAC control module.

Alternate Method (without Scan Tool)

NOTE: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result

1. Clear all DTCs.
2. Ignition OFF.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Remove the HVAC control module fuse for a minimum of 10 s.
6. Install the HVAC control module fuse.
7. Start the vehicle.
8. Wait 40 s for the HVAC control module to self-calibrate.

READ NEXT: