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HVAC System - Automatic: Diagnosis GMC Terrain I

Automatic HVAC System ~6381 words

Diagnostic Code Index

DTCDescription
DTC B0163DTC B0163 02 Passenger Compartment Temperature Sensor Circuit Short to Ground DTC B0163 05 Passenger Compartment Temperature Sensor Circuit High Voltage/Open
DTC B0173, B0178, or B3933DTC 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 B3933 02 Air Conditioning Evaporator Temperature Sensor Circuit Short to Ground DTC B3933 05 Air Conditioning Evaporator Temperature Sensor Circuit High Voltage/Open
DTC B018A, B048C, B048F, or B1395DTC B018A 02 Windshield Temperature Sensor Circuit Short to Ground DTC B018A 05 Windshield Temperature Sensor Circuit High Voltage/Open DTC B048C 02 Humidity Sensor Humidity Circuit Short to Ground DTC B048C 05 Humidity Sensor Humidity Circuit High Voltage/Open DTC B048F 02 Humidity Sensor Temperature Circuit Short to Ground DTC B048F 05 Humidity Sensor Temperature Circuit High Voltage/Open DTC B1395 03 Control Module Voltage Reference Output Circuit Low Voltage DTC B1395 07 Control Module Voltage Reference Output Circuit High Voltage
DTC B0183DTC B0183 02 Solar Load Sensor Circuit Short to Ground DTC B0183 05 Solar Load Sensor Circuit High Voltage/Open
DTC B0193DTC B0193 01 Front Blower Motor Speed Circuit Short to Battery DTC B0193 06 Front Blower Motor Speed Circuit Low Voltage/Open
DTC B0228, B0413, B1395, or B374ADTC B0228 02 Left Recirculate Position Feedback Circuit Short to Ground DTC B0228 05 Left Recirculate Position Feedback Circuit High Voltage/Open DTC B0413 02 Main Temperature Control Feedback Circuit Short to Ground DTC B0413 05 Main Temperature Control Feedback Circuit High Voltage/Open DTC B1395 03 Control Module Voltage Reference Output Circuit Low Voltage DTC B1395 07 Control Module Voltage Reference Output Circuit High Voltage DTC B374A 02 Air Flow Control Feedback Circuit Short to Ground DTC B374A 05 Air Flow Control Feedback Circuit High Voltage/Open
DTC B393BDTC B393B 04 Air Conditioning Compressor Valve Control Circuit Open DTC B393B 0B Air Conditioning Compressor Valve Control Circuit High Current
DTC P0532 or P0533DTC P0532 00 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage DTC P0533 00 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage
DTC P0645DTC P0645 Air Conditioning (A/C) Compressor Clutch Relay Control Circuit

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Signal Terminal 3B0163 02B0163 05B0163 051
Low ReferenceB0163 05, B0183 05
1. HVAC Malfunction

Conditions for Running the DTC

  1. Ignition ON
  2. 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.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the B10B ambient light/ sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 scan tool parameter Passenger Compartment Air Temperature (Unfiltered) is less than -35°F. If -35°F or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 -35°F
  5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.
  6. Verify the scan tool parameter Passenger Compartment Air Temperature (Unfiltered) is greater than 240°F. If 240°F or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. 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 Ignition OFF 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 240°F
  7. Test or replace the B10B ambient light sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
  1. Ignition ON
  2. The HVAC control module is ON.

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.

The system operates using a default value.

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

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate B7 temperature sensor It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the low reference circuit terminal 2 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 control module. If less than 10 ohms
  3. Ignition ON.
  4. Verify the appropriate scan tool Temperature Sensor parameter is less than -35°C (-39°F). If -35°C (-39°F) or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 1 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 -35°C (-39°F)
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.
  6. Verify the scan tool temperature sensor parameter is greater than 85°C (185°F). If 85°C (185°F) or greater Ignition OFF, disconnect the harness connector at the HVAC control module, ignition ON. 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 Ignition OFF 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 0.1 V
  7. Test or replace the temperature sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceB1395 03B1395 07
Signal Terminal 2B048C 02B048C 05B048C 05
Signal Terminal 5B048F 02B048F 05B048F 05
Signal Terminal 4B018A 02B018A 05B018A 05
GroundB018A 05, B048C 05, B048F 05
  1. Ignition ON.
  2. The HVAC control module is ON.

B018A 02, B048C 02, B048C 02 or B1395 03

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, B048C 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.

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

The condition for setting the DTC is no longer present.

DTC B1395

  1. Ignition OFF, disconnect the harness connector at the components listed below: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator
  2. Disconnect the X3 harness connector at the K33 HVAC control module, ignition ON.
  3. Test for less than 1 V between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
  4. Ignition OFF.
  5. Test for infinite resistance between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
  6. Clear all DTCs, connect the X3 harness connector at the K33 HVAC control module, ignition ON.
  7. Verify DTC B1395 is not set. If the DTC is set. Replace the K33 HVAC control module. If the DTC is not set.
  8. Verify DTC B1395 does not set after connecting each of the components listed below, one at a time: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator If the DTC sets after connecting one of the components Replace the component that was connected immediately before the DTC set. If the DTC does not set
  9. All OK.

DTC B018A, B048C, or B048F

  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 2 minutes for all vehicle systems to power down.
  2. Test for less than 60 ohms between the low reference circuit terminal 3 and ground. If 60 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 60 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 Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 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 Ignition OFF, disconnect the harness connector at the K33 HVAC control module, Ignition ON. 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 -37°C (-35°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If -37°C (-35°F) or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 -37°C (-35°F)
  6. Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%. If 95% or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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%
  7. Install a 3 A fused jumper wire between each signal circuit terminal listed below and the low reference circuit terminal 3 one at a time. Windshield temperature sensor signal terminal 4 Passenger compartment humidity sensor temperature signal terminal 5
  8. Verify the appropriate scan tool parameter listed below is greater than 114°C (238°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If 114°C (238°F) or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 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 114°C (238°F)
  9. Install a 3 A fused jumper wire between the passenger compartment humidity sensor signal circuit terminal 2 and the low reference circuit terminal 3.
  10. Verify the scan tool Passenger Compartment Humidity parameter is less than 5%. If 5% or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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%
  11. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, Ignition ON.
  12. 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
  13. Test or replace the B160 windshield temperature and inside moisture sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalB0183 05B0183 02B0183 021
Low ReferenceB0163 05, B0183 05
1. Air Temperature Malfunction
  1. Ignition ON
  2. The HVAC Control Module is ON.

B0183 02

The input signal is out of range. The voltage is less than 0.1 V.

B0183 05

The input signal is out of range. The voltage is greater than 4.9 V.

  1. The system will use the last valid values as default.
  2. If no value is read at the time of fault, the HVAC control module uses 0 W/m 2 as intensity.

The condition for setting the DTC is no longer present.

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B ambient light/ sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 Sunload scan tool parameter is less than 2 W/m2. If 2 W/m2 or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 4 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 2 W/m2
  5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 6.
  6. Verify the scan tool parameter is greater than 20 W/m2. If 20 W/m2 or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the signal circuit terminal 4 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF 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 20 W/m2
  7. Test or replace the B10B ambient light sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+B0193 06B0193 06
ControlB0193 06B0193 06B0193 01
GroundB0193 06
  1. Ignition ON.
  2. The HVAC control module is ON.

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 floating.

The blower motor is inoperative.

The condition for setting the DTC is no longer present.

Diagnostic Aids

Prior to motor replacement connect a direct independent B+ and ground to verify operation.

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

If the motor operates properly please reinstall it, check for PIs or TSBs, and refer to Testing for Intermittent Conditions and Poor Connections in the appropriate Electrical Information Reference information.

  1. Ignition OFF, disconnect the X1 harness connector at the K8 blower motor control module. It may take up to 2 minutes 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 Ignition OFF. 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, verify a test lamp illuminates between B+ circuit terminal 6 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. 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 Ignition OFF. 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, replace the K8 blower motor control module. If the test lamp illuminates
  4. Connect a DMM between the control circuit X1 terminal 3 and the B+ circuit terminal 6.
  5. Verify the proper voltages when changing the blower speed positions. OFF 13.0 V-10.0 V HI 4.0 V-1.0 V If not within the specified range Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 1 V between the control circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V 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 within the specified range
  6. Connect the X1 harness connector at the K8 blower motor control module. Disconnect the harness connector at the M8 blower motor.
  7. Connect a DMM between the control circuit terminal A and B+.
  8. Verify the proper voltages when changing the blower speed positions. OFF 0 V-3.0 V HI 10.0 V-13.0 V If not within the specified range Ignition OFF, disconnect the harness connector X2 at the K8 blower motor control module. 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 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 within the specified range
  9. Verify a test lamp illuminates between B+ circuit terminal B and ground. If the test lamp does not illuminate Ignition OFF. 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. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the M8 blower motor. If the test lamp illuminates
  10. All OK.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Recirculation Actuator 5V ReferenceB1395 03B1395 07B1395 07
Air Temperature Actuator 5V ReferenceB1395 03B1395 07B1395 07
Mode Actuator 5V ReferenceB1395 03B1395 07B1395 07
Recirculation Actuator SignalB0228 02B0228 05B0228 051
Air Temperature Actuator SignalB0413 02B0413 05B0413 052
Mode Actuator SignalB374A 02B374A 05B374A 053
Recirculation Actuator Control 11111
Recirculation Actuator Control 21111
Air Temperature Actuator Control 12222
Air Temperature Actuator Control 22222
Mode Actuator Control 13333
Mode Actuator Control 23333
Recirculation Actuator Low ReferenceB0228 05B0228 05
Air Temperature Actuator Low ReferenceB0413 05B0413 05
Mode Actuator Low ReferenceB374A 05B374A 05
Air Recirculation Malfunction Air Temperature Malfunction Air Distribution Malfunction
  1. Ignition ON.
  2. The HVAC control module is ON.

B0228 02, B0413 02 or B374A 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.

B0228 05, B0413 05 or B374A 05

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 sensor reference voltage out of range. The reference voltage is less than 0.1 V for more than 50 ms.

B1395 07

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

B1395

  1. The affected output will be switched off for hardware protection.
  2. All actuators are deactivated.

B0228, B0413, or B374A

  1. The affected output will be switched off for hardware protection.
  2. The affected actuator is deactivated.

The condition for setting the DTC is no longer present.

DTC B1395

  1. Ignition OFF, disconnect the harness connector at the components listed below: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator
  2. Disconnect the X3 harness connector at the K33 HVAC control module, ignition ON.
  3. Test for less than 1 V between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
  4. Ignition OFF.
  5. Test for infinite resistance between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
  6. Clear all DTCs, connect the X3 harness connector at the K33 HVAC control module, ignition ON.
  7. Verify DTC B1395 is not set. If the DTC is set. Replace the K33 HVAC control module. If the DTC is not set.
  8. Verify DTC B1395 does not set after connecting each of the components listed below, one at a time: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator If the DTC sets after connecting one of the components Replace the component that was connected immediately before the DTC set. If the DTC does not set
  9. All OK.

DTC B0228, B0413, or B374A

  1. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes 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 Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 3 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 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. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. 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. If between 4.8-5.2 V
  5. Ignition ON.
  6. Verify the scan tool Door Position parameter is less than 5 counts. If 5 counts or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. 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, replace the K33 HVAC control module. If less than 5 counts
  7. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the 5 V reference circuit terminal 3.
  8. Verify the scan tool Door Position parameter is greater than 250 counts. If 250 counts or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 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 250 counts.
  9. Replace the actuator.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
  1. Ignition ON.
  2. The HVAC control module is ON.

B393B 04

A PWM greater than 10% is send out but no current is read back.

B393B 0B

Measured current is above threshold of 815 mA.

B393B 04

The A/C compressor is disabled.

B393B 0B

  1. The A/C compressor is disabled.
  2. Output will be switched off for hardware protection.

The condition for setting the DTC is no longer present.

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q46 A/C compressor solenoid valve. It may take up to 2 minutes for all vehicle systems to power down.
  2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. 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 Ignition OFF. Test for infinite resistance between the B+ 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 illuminates
  3. Connect a test lamp between the control circuit terminal 1 and the B+ circuit terminal 2.
  4. Verify the test lamp turns ON and OFF when Commanding the A/C Compressor Refrigerant Solenoid Valve ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. 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 Ignition OFF. 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 the test lamp is always ON Ignition OFF, disconnect the harness connector at the K33 HVAC control module. 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 turns ON and OFF
  5. Test or replace the Q46 A/C compressor solenoid valve.

Component Testing

Static Test

  1. Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
  2. Test for 7-15 ohms between B+ circuit terminal 2 and control circuit terminal 1. If not within the specified range, replace the Q46 Air Conditioning Compressor Valve.
  3. Test for infinite resistance between each terminal and the Q46 Air Conditioning Compressor Valve housing/case. If not the specified value, replace the Q46 Air Conditioning Compressor Valve.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0532 00P0532 00
SignalP0532 00P0532 00P0533 00
Low ReferenceP0532 00

Engine is running.

P0530 03 or P0532 00

The ECM detects a short to ground or open at the A/C pressure sensor signal circuit.

P0530 07 or P0533 00

The ECM detects a short to voltage at the A/C pressure sensor signal circuit.

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

The condition for setting the DTC is no longer present.

  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 minutes 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 Ignition OFF, disconnect the harness connector at the K20 ECM. 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 ECM. 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 Ignition OFF, disconnect the harness connector at the K20 ECM control module. 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 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 ECM. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K20 ECM control module, ignition ON. 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 ECM. If between 4.8-5.2 V
  5. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 4.8-5.2 V. If 4.8-5.2 V or greater Ignition OFF, disconnect the harness connector at the K20 ECM, ignition ON. 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 ECM. If less than 4.8-5.2 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.02 V. If.02 V or less Ignition OFF, disconnect the harness connector at the K20 ECM. 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 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 ECM. If greater than.02 V
  8. Test or replace the B1 A/C refrigerant pressure sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ControlP0645P0645P0645
  1. Engine is running.
  2. The HVAC control module is ON.
  3. The A/C switch is active.

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

The A/C compressor is inoperative.

The condition for setting the DTC is no longer present.

  1. Ignition OFF, disconnect the KR29 A/C compressor clutch relay, ignition ON.
  2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. 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 Ignition OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, Test for greater than 1 ohms between the control circuit terminal A and ground. If less than 1 ohms, repair the short to ground on the circuit. If greater than 1 ohms, test or replace the KR29 A/C compressor clutch relay. If the test lamp illuminates
  3. Verify a test lamp illuminates between the ignition circuit terminal 85 and ground. If the test lamp does not illuminate Replace the X50A underhood fuse block. If the test lamp illuminates
  4. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
  5. Verify the test lamp turns ON and OFF when commanding the A/C compressor clutch ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K20 ECM, ignition ON. 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 Ignition OFF. 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 K20 ECM. If the test lamp is always ON Ignition OFF, disconnect the harness connector at the K20 ECM. 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 K20 ECM. If the test lamp turns ON and OFF
  6. Verify a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates Repair the short to voltage on the circuit. If the test lamp does not illuminate
  7. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q2 A/C compressor clutch.
  8. Test for less than 10 ohms between the Q2 A/C compressor clutch ground circuit terminal B and ground. If 10 ohms or greater Ignition OFF. 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
  9. Connect the harness connector at the Q2 A/C compressor clutch.
  10. Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
  11. Verify the Q2 A/C compressor clutch is activated. If the Q2 A/C compressor clutch does not activate Ignition OFF. Test for less than 2 ohms in the control circuit terminal 87 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
  12. Test or replace the KR29 A/C compressor clutch relay.

Visual/Physical Inspection

  1. Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(ref-491170-S38135034022012073000000) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
  3. Verify the A/C compressor turns freely and is not seized.
  4. Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
  5. The A/C compressor will not operate in cold outside air temperatures.
  6. 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
  7. 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

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Air Temperature Malfunction»(ref-491160-S02077464862012073000000)
  2. «Air Delivery Improper»(ref-491160-S27905289042012073000000)
  3. «Air Recirculation Malfunction»(ref-491160-S40846080202012073000000)
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Air Temperature Actuator 5V ReferenceB1395 03B1395 07B1395 07
Air Temperature Actuator Control 11111
Air Temperature Actuator Control 21111
Air Temperature Actuator SignalB0413 02B0413 05B0413 051
Air Temperature Actuator Low ReferenceB0413 05B0413 05
1. Air Temperature Malfunction

Check the following mechanical fault sources

  1. Air distribution box
  2. Air distribution hoses/air distribution ducts
  1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
  2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each 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 turns ON for each command
  3. Replace the M6 Air Temperature Door Actuator.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Mode Actuator 5V ReferenceB1395 03B1395 07B1395 07
Mode Actuator Control 11111
Mode Actuator Control 21111
Mode Actuator SignalB374A 02B374A 05B374A 051
Mode Actuator Low ReferenceB374A 05B374A 05
1. Air Delivery Improper

Check the following mechanical fault sources

  1. Air distribution box
  2. Air distribution hoses/air distributing ducts
  1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
  2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each 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 turns ON for each command
  3. Replace the M37 Mode Door Actuator.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-491140-S09841272902012073000000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-491140-S29106564382012073000000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Recirculation Actuator 5V ReferenceB1395 03B1395 07B1395 07
Recirculation Actuator Control 11111
Recirculation Actuator Control 21111
Recirculation Actuator SignalB0228 02B0228 05B0228 051
Recirculation Actuator Low ReferenceB0228 05B0228 05
1. Air Recirculation Malfunction

Check the following mechanical fault sources

  1. Air distribution box
  2. Air distribution hoses/air distribution ducts
  1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
  2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each 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 turns ON for each command
  3. Replace the M46 Air Recirculation Door Actuator.

More articles — HVAC System - Automatic