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HVAC System - Automatic: Diagnosis Chevrolet Volt I

Automatic HVAC System ~11407 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 B0223, B0233, B023A, or B0408DTC B0223 01 Recirculate Position Command 1 Circuit Short to Battery DTC B0223 06 Recirculate Position Command 1 Circuit Short to Ground or Open DTC B0233 01 Air Flow Control Circuit Short to Battery DTC B0233 06 Air Flow Control Circuit Short to Ground or 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 Short to Ground or Open
DTC B0468, B046B, or B046CDTC B0468 01 Auxiliary Heater Coolant Pump Circuit Short to Battery DTC B0468 06 Auxiliary Heater Coolant Pump Circuit Low Voltage/Open DTC B046B 00 Auxiliary Heater Coolant Pump Feedback Circuit DTC B046C 02 Auxiliary Heater Coolant Pump Enable Circuit Short to Ground DTC B046C 05 Auxiliary Heater Coolant Pump Enable Circuit High Voltage/Open
DTC B046ADTC B046A 02 Auxiliary Heater Coolant Pump Temperature Circuit Short to Ground DTC B046A 05 Auxiliary Heater Coolant Pump Temperature Circuit Short to Battery or Open
DTC P0071-P0073DTC P0071 Ambient Air Temperature Sensor Performance DTC P0072 Ambient Air Temperature Sensor Circuit Low Voltage DTC P0073 Ambient Air Temperature Sensor Circuit High Voltage
DTC P0531, P0532, or P0533DTC P0531 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit DTC P0532 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage DTC P0533 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage
DTC P0534DTC P0534 Air Conditioning (A/C) Refrigerant Charge Low
DTC P0536-P0538 or P153BDTC P0536 Air Conditioning (A/C) Evaporator Temperature Sensor 2 Performance DTC P0537 Air Conditioning (A/C) Evaporator Temperature Sensor 2 Circuit Low Voltage DTC P0538 Air Conditioning (A/C) Evaporator Temperature Sensor 2 Circuit High Voltage DTC P153B Air Conditioning (A/C) Evaporator Temperature Sensor 2 Not Plausible
DTC P0D69-P0D7FDTC P0D69 A/C Compressor Motor Voltage Sensor Performance DTC P0D6A A/C Compressor Motor Voltage Sensor Circuit High Voltage DTC P0D6B A/C Compressor Motor Voltage Sensor Circuit Low Voltage DTC P0D6F A/C Compressor Motor High Current DTC P0D71 Electric A/C Compressor Control Module Temperature Sensor Performance DTC P0D72 Electric A/C Compressor Control Module Temperature Sensor Circuit High Voltage DTC P0D73 Electric A/C Compressor Control Module Temperature Sensor Circuit Low Voltage DTC P0D76 Electric A/C Compressor Control Module Output Driver Temperature Sensor Performance DTC P0D77 Electric A/C Compressor Control Module Output Driver Temperature Sensor Circuit High Voltage DTC P0D78 Electric A/C Compressor Control Module Output Driver Temperature Sensor Circuit Low Voltage DTC P0D7A A/C Compressor Motor Phase U Low Current DTC P0D7B A/C Compressor Motor Phase U High Current DTC P0D7C A/C Compressor Motor Phase V Low Current DTC P0D7D A/C Compressor Motor Phase V High Current DTC P0D7E A/C Compressor Motor Phase W Low Current DTC P0D7F A/C Compressor Motor Phase W High Current
DTC P0AF8DTC P0AF8 03 Hybrid System Voltage
DTC P151C or P2516-P2518DTC P151C Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Not Plausible DTC P2516 Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Performance DTC P2517 Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Circuit Low Voltage DTC P2518 Air Conditioning (A/C) Low Side Refrigerant Pressure Sensor Circuit High Voltage
DTC P1ECA or P1EC9DTC P1ECA A/C Compressor Motor Instantaneous High Voltage DTC P1EC9 A/C Compressor Motor Instantaneous High Current
DTC P1F0A-P1F0DDTC P1F0A A/C Compressor Motor Speed Performance DTC P1F0B A/C Compressor Motor Start-Up Current Performance DTC P1F0C Electric A/C Compressor Control Module A/C Compressor Motor Current Feedback Circuit Low Voltage DTC P10FD Electric A/C Compressor Control Module A/C Compressor Motor Current Feedback Circuit High Voltage
DTC P2681, P26A3, P26A6, P26A7, or P26A9DTC P2681 Engine Coolant Bypass Valve Control Circuit DTC P26A3 Engine Coolant Bypass Valve Performance DTC P26A6 Engine Coolant Bypass Valve Position Sensor Circuit Low Voltage DTC P26A7 Engine Coolant Bypass Valve Position Sensor Circuit High Voltage DTC P26A9 Engine Coolant Bypass Valve Position Sensor Stop Performance

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Inside Air Temperature Sensor Signal Terminal 3B0163 02B0163 05B0163 05
Twilight Sentinel Delay Sensor Signal Terminal 4B0183 02B0183 05B0183 05
Low ReferenceB0163 05, B0183 05

Conditions for Running the DTC

  1. Vehicle in Service Mode.
  2. The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02 or B0163 05

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

  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 .

Conditions for Clearing the DTC

B0163 02 or B0163 05

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

Circuit/System Testing

  1. Vehicle 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 60 ohms between the low reference circuit terminal 6 and ground. If 60 ohms or greater Vehicle 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. Vehicle in Service Mode.
  4. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is less than-37°C (-35°F). If -37°C (-35°F) or greater Vehicle 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 -37°C (-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 Passenger Compartment Air Temperature (Unfiltered) parameter is greater than 110°C (240°F). If 110°C (240°F) or less Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode. 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 Vehicle 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 110°C (240°F)
  7. Test or replace the B10B ambient light sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Upper Left Duct Air Temperature Sensor SignalB0173 02B0173 05B0173 05
Lower Left Duct Air Temperature Sensor SignalB0178 02B0178 05B0178 05
Air Conditioning Evaporator Temperature Sensor SignalB3933 02B3933 05B3933 05
Low ReferenceB0173 05, B0178 05, B3933 05

The vehicle is turned 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.

A default value is used when the DTC is set.

  1. The DTC will become history if the HVAC control module no longer detects a failure.
  2. The history DTC will clear after 100 fault-free ignition cycles.
  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 50 ohms between the low reference circuit terminal B and ground. If 50 ohms or greater Vehicle 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 50 ohms
  3. Vehicle in Service Mode.
  4. Verify the scan tool parameter is less than -37°C (-35°F). Lower Left Duct Air Temperature Sensor Upper Left Duct Temperature Sensor A/C Evaporator Temperature Sensor If greater than -37°C (-35°F) Vehicle OFF, disconnect the harness connector at the K33 HVAC control module. 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 -37°C (-35°F) or less
  5. Install a 3 A fused jumper wire between the signal circuit and the low reference circuit terminal B.
  6. Verify the scan tool parameter is greater than 110°C (230°F). Lower Left Duct Air Temperature Sensor Upper Left Duct Temperature Sensor A/C Evaporator Temperature Sensor If 110°C (230°F) or less Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode. 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 Vehicle 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 110°C (230°F)
  7. Test or replace the temperature sensor.

Component Testing

  1. Vehicle OFF, disconnect the temperature sensor.
  2. Test the temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
  3. Verify that the resistance is within 5 percent of the specification while comparing the readings with the «Sensor Resistance Table»(ref-487453-S31537582972012072300000) . If not within the specified range Replace the sensor If within the specified range
  4. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) 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. Vehicle ON or Vehicle in Service Mode.
  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.

  1. Vehicle 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 Vehicle 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. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Vehicle 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 Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode. 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 Vehicle 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 Vehicle 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 Vehicle 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 Vehicle 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. Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode.
  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-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Sensor Signal Terminal 3B0163 02B0163 05B0163 051
Sensor Signal Terminal 4B0183 02B0183 05B0183 051
Low ReferenceB0163 05, B0183 05
1. HVAC Malfunction
  1. Vehicle in Service Mode.
  2. The HVAC control module is ON.

B0163 02 or B0163 05

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.

B0183 02

The 5 V identification pulse is not received.

B0183 05

The input signal is static and greater than 4.8 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 .

B0163 02 or B0163 05

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

B0183 02 or B0183 05

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

  1. Vehicle 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 60 ohms between the low reference circuit terminal 6 and ground. If 60 ohms or greater Vehicle OFF, disconnect the X1 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. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the signal circuit terminal 4 and ground. If less than 4.8 V Vehicle OFF, disconnect the X1 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 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 Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module, Vehicle in Service Mode. 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
  5. Replace the B10B ambient light sensor.
  6. Verify DTC B0183 does not set while operating the vehicle under the Conditions for Running the DTC. If the DTC sets Replace the K33 HVAC control module If the DTC does not set
  7. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+ Terminal 6 X1B0193 06B0193 06
B+ Terminal 1 X2111
Blower Motor Speed Control Terminal 3 X1B0193 06B0193 06B0193 01
Blower Motor Ground Control Terminal 2 X2111
Ground1
1. Blower motor malfunction.
  1. Vehicle in Service Mode.
  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.

  1. Vehicle OFF and all vehicle systems 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 Vehicle 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. Vehicle in Service Mode.
  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 Vehicle 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 Vehicle 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 K8 blower motor control module. If the test lamp illuminates
  5. Vehicle in Service Mode.
  6. Test for greater than 11 V between the B+ terminal 6 and the control circuit terminal 3. If less than 11 V Vehicle OFF, disconnect the harness connector at the K33 HVAC 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 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 11 V or greater
  7. Verify the voltage reading changes 0.01 V or greater with each blower speed change. If the voltage reading does not change Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode. 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 voltage reading changes
  8. Vehicle OFF, disconnect the X2 harness connector at the K8 blower control module.
  9. Install a 10 A fused jumper wire between the B+ circuit terminal 1 X2 and the B+ circuit terminal 6 X1.
  10. Verify the M8 blower motor turns on when installing a jumper wire between the control circuit terminal 2 X2 and ground. If the blower motor does not turn on Replace the M8 blower motor If the blower motor turns on
  11. All OK.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Stepper Motors 12 V ReferenceB023A 02B0223 06, B0233 06, B0408 06, 1
Recirculation Actuator Control 1B0223 06, 1B0223 06, 1B0223 01, 1
Recirculation Actuator Control 2B0223 06, 1B0223 06, 1B0223 01, 1
Recirculation Actuator Control 3B0223 06, 1B0223 06, 1B0223 01, 1
Recirculation Actuator Control 4B0223 06, 1B0223 06, 1B0223 01, 1
Air Temperature Actuator Control 1B0408 06, 1B0408 06, 1B0408 01, 1
Air Temperature Actuator Control 2B0408 06, 1B0408 06, 1B0408 01, 1
Air Temperature Actuator Control 3B0408 06, 1B0408 06, 1B0408 01, 1
Air Temperature Actuator Control 4B0408 06, 1B0408 06, 1B0408 01, 1
Mode Actuator Control 1B0233 06, 1B0233 06, 1B0233 01, 1
Mode Actuator Control 2B0233 06, 1B0233 06, 1B0233 01, 1
Mode Actuator Control 3B0233 06, 1B0233 06, 1B0233 01, 1
Mode Actuator Control 4B0233 06, 1B0233 06, 1B0233 01, 1
1. Actuator door malfunction
  1. Vehicle on, or in Service Mode.
  2. The HVAC control module is ON.

B023A 02

The stepper motors supply output is shorted to ground.

B0223 01, B0233 01 or B0408 01

At least one control output (of 4 possible outputs) 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, B0233 06 or B0408 06

At least one control output (of 4 possible outputs) 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.

B023A 02

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

B0223, B0233 or B0408

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

The condition for setting the DTC is no longer present.

  1. Vehicle OFF, disconnect the harness connector at the appropriate door actuator, vehicle in Service Mode.
  2. Connect a test lamp between the B+ circuit terminal 2 and ground.
  3. Verify the test lamp turns ON then OFF when commanding the appropriate actuator listed below ON but not OFF with a scan tool. Mode Door Position Air Recirculation Door Actuator Direction Left Temperature Door Actuator Direction If the test lamp is always OFF Vehicle OFF, disconnect the X3 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 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 Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode. 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 the test lamp turns ON then OFF
  4. Vehicle OFF, disconnect the X3 harness connector at the K33 HVAC control module, vehicle in Service Mode.
  5. Test for less than 1 V between each control circuit terminal listed below and ground. Control Circuit - terminal 1 Control Circuit - terminal 3 Control Circuit - terminal 4 Control Circuit - terminal 6 If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
  6. Vehicle OFF.
  7. Test for infinite resistance between each control circuit terminal listed below and ground. Control Circuit - terminal 1 Control Circuit - terminal 3 Control Circuit - terminal 4 Control Circuit - terminal 6 If less than infinite resistance Repair the short to ground on the circuit. If Infinite resistance
  8. Test for less than 2 ohms in each control circuit listed below end to end. NOTE: See schematic for the K33 HVAC control module terminal numbers. Control circuit terminal 1 Control circuit terminal 3 Control circuit terminal 4 Control circuit terminal 6 If 2 ohms or greater Repair the open/high resistance in the circuit. If less than 2 ohms
  9. Test or replace the actuator.
  10. Verify the DTC does not set and the correct door position is achieved while operating the HVAC system under the Conditions for Running the DTC. If the DTC sets or door position is incorrect Replace the K33 HVAC control module. If the DTC does not set and door position is correct
  11. All OK.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+B046B 00B046B 00
Control Terminal 1B046C 02B0468 06, B046B 00, B046C 05B046C 05
Control Terminal 3B0468 06B0468 06B0468 01
SignalB046B 00B046B 00B046B 00
GroundB046B 00

B0468 01

  1. The 12 V battery system voltage is greater than 9 V.
  2. Vehicle ON.
  3. The HVAC system is turned ON.

B0468 06

  1. The 12 V battery system voltage is greater than 9 V.
  2. Vehicle ON.
  3. The HVAC system is turned ON.

B046B 00

  1. The 12 V battery system voltage is greater than 9 V.
  2. Vehicle ON.
  3. The HVAC system is turned ON.

B046C 02

  1. The 12 V battery system voltage is greater than 9 V.
  2. Vehicle ON.
  3. The HVAC system is turned ON.

B046C 05

  1. The 12 V battery system voltage is greater than 9 V.
  2. Vehicle ON.
  3. The HVAC system is turned ON.

B0468 01

Requested PWM is not zero and the feedback from the Auxiliary Heater is always High.

B0468 06

Feedback from the auxiliary heater voltage is always low or floating.

B046B 00

PWM duty cycle/ frequency out of range

B046C 02

PWM duty cycle/ frequency out of range

B046C 05

PWM duty cycle/ frequency out of range

The auxiliary heater coolant pump is disabled.

B0468 01

Feedback of auxiliary heater output corresponds with requested PWM signal.

B0468 06

Feedback of auxiliary heater output corresponds with requested PWM signal.

B046B 00

PWM duty cycle / frequency is within defined range

B046C 02

Requested status of the output is ON and feedback shows normal operation

B046C 05

Requested status of the output is OFF and feedback shows normal operation

Diagnostic Aids

A DTC B0468 may cause a DTC B046B or DTC B046C to set.

  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the G36 auxiliary heater coolant pump. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 4 and ground. If 5 ohms or greater Vehicle 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 5 ohms
  3. Vehicle in Service Mode.
  4. Verify a test lamp illuminates between the B+ circuit terminal 5 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle 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 Vehicle 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 G36 auxiliary heater coolant pump. If the test lamp illuminates
  5. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 4, Vehicle in Service Mode and the HVAC system OFF.
  6. Verify the test lamp turns ON and OFF when commanding the Auxiliary Coolant Pump Speed Command ON and OFF with a scan tool. If the test lamp is always OFF Vehicle 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 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 Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, Vehicle in Service Mode. 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 the test lamp turns ON and OFF
  7. Install a 3 A fused jumper wire at the ground circuit terminal 4, Vehicle in Service Mode.
  8. Verify the scan tool Auxiliary Coolant Pump Speed Feedback Frequency parameter changes while rapidly tapping the fused jumper wire to the signal circuit terminal 2. If the parameter does not change Vehicle in Service Mode, disconnect the harness connector at the K33 HVAC control module. 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 Vehicle OFF 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 the parameter changes
  9. Connect a DMM between the control circuit terminal 3 and ground, Vehicle in Service Mode.
  10. Verify the resistance reading changes when commanding the Auxiliary Coolant Pump Speed Command ON and OFF with a scan tool. If the resistance reading does not change Vehicle in Service Mode, disconnect the harness connector at the K33 HVAC 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 Vehicle OFF 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 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 resistance reading changes
  11. Replace the Q36 auxiliary heater coolant pump.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Signal circuitB046A 02B046A 05B046A 05
Low ReferenceB018A 05, B048C 05, B048F 05

Circuit Description

The HVAC control module supplies the coolant heater temperature sensor with a low reference circuit and 5 V signal circuit. The HVAC control module determines the voltage drop across the sensor, which is proportional to temperature. As the temperature increases, the sensor resistance decreases and the voltage signal decreases. As the temperature decreases, the sensor resistance increases and the voltage signal increases.

Vehicle ON or vehicle in Service Mode.

The HVAC control module detects the coolant heater temperature sensor signal circuit is less than -38°C (-38°F) or greater than 85°C (185°F).

A default value is used when the DTC is set.

  1. The DTC will become history if the conditions for setting the DTC are no longer present.
  2. The history DTC will clear after 100 fault-free vehicle ON cycles.
  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B135 coolant heater temperature 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 2 and ground. If 60 ohms or greater Vehicle 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. Vehicle in Service Mode.
  4. Verify the scan tool Heater Core Coolant Temperature Sensor parameter is less than -37°C (-35°F). If -37°C (-35°F) or greater Vehicle 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 less than -37°C (-35°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 Heater Core Coolant Temperature Sensor parameter is greater than 115°C (240°F). If 115°C (240°F) or less Vehicle OFF, disconnect the harness connector at the K33 HVAC control module, vehicle in Service Mode. 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 Vehicle 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 115°C (240°F)
  7. Test or replace the B135 coolant heater temperature sensor.
  1. Vehicle OFF, disconnect the coolant heater temperature sensor.
  2. Test the temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
  3. Verify that the resistance is within 5 percent of the specification while comparing the readings with the «Temperature Versus Resistance»(ref-487511-S02115377072012072300000) . If not within the specified range Replace the sensor If within the specified range
  4. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0072P0072P0073P0071
Low ReferenceP0073P0071

Vehicle in Service Mode.

The Hybrid/EV Powertrain Control Module 2 detects the ambient air temperature sensor signal circuit is less than -35°C (-39°F) or more than 85°C (185°F) for more than 15 seconds.

  1. The DIC will display SERVICE A/C SYSTEM.
  2. The system operates using a default value.
  1. The DTC will become history if the Hybrid/EV Powertrain Control Module 2 no longer detects the condition that set the DTC.
  2. The history DTC will clear after 100 fault-free ignition cycles.
  1. Vehicle OFF, disconnect the harness connector at the B9 ambient air temperature sensor.
  2. Verify a test lamp illuminates between the low reference circuit terminal B and B+. If the test lamp does not illuminate Vehicle OFF disconnect the harness connector X1 at the K114B hybrid powertrain 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 K114B hybrid powertrain control module 2 If the test lamp illuminates
  3. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the signal circuit terminal A and ground. If less than 4.8 V Vehicle OFF, disconnect the harness connector X1 at the K114B hybrid powertrain 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 Test for less than 2 ohms on 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 K114B hybrid powertrain control module 2. If greater than 5.2 V Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2, Vehicle in Service Mode. 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 hybrid powertrain control module 2. If between 4.8-5.2 V
  5. Test or replace the B9 ambient air temperature sensor.
  6. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC. If the DTC sets Replace the K114B hybrid powertrain control module 2 If the DTC does not set
  7. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of the diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0452, P0532, P0641P0532P0453, P0533, P0641
SignalP0532P0532P0533
Low ReferenceP0533
  1. Engine is running.
  2. Any of the conditions for setting the DTC are met for 15 seconds.
  3. Battery voltage is between 11-18 V.
  1. The engine control module detects that the A/C pressure is less than.25 V.
  2. The engine control module detects that the A/C pressure is greater than 4.75 V.

This is a type D DTC.

This is a type D DTC.

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

  1. Vehicle 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 5 ohms between the low reference circuit terminal 1 and ground. If 5 ohms or greater Vehicle OFF, disconnect the harness connector at the K20 engine 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 K20 engine control module. If less than 5 ohms
  3. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground. If less than 4.8 V vehicle OFF, disconnect the harness connector at the K20 engine 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 engine control module. If greater than 5.2 V Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode. 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 engine control module A/C High Side Pressure Sensor parameter is less than.25 V. If.25 V or greater Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode. 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 4.75 V. If 4.75 V or less Vehicle OFF, disconnect the harness connector at the K20 engine 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 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 4.75 V
  8. Test or replace the B1 A/C refrigerant pressure sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

DTC P0534 Case 1

  1. 12V battery system voltage is equal to or greater than 10.25V
  2. The air conditioning compressor control module has 300V
  3. The A/C compressor motor is running for at least 30 seconds.
  4. Must be in battery active cooling mode for at least 1 minute
  5. The following DTCs must not be set: P0CE0; P0CE2; P0CE3; P0CE6; P0CE7; P1CE7; P1CE8, P0C47; P0C4A, P1F18, P0C44, P0C45, P0C43, P0CD6, p0CD7, P0CD8, P0071; P0072; P0073

DTC P0534 Case 2

  1. 12V battery system voltage is equal to or greater than 10.25V
  2. AC compressor off for greater than 240 seconds
  3. Outside air temperature greater than 15C. (59F)
  4. The following DTCs must not be set: P2516, P2517, P2518, P0606, P0071, P0072, P0073

DTC P0534 Case 3

  1. 12V battery system voltage is equal to or greater than 10.25V
  2. AC compressor on for greater than 240 seconds
  3. Outside air temperature greater than 5C (41F).
  4. The following DTCs must not be set: P2516, P2517, P2518, P0606, P0071, P0072, P0073

DTC P0534 Case 4

  1. 12V battery system voltage is equal to or greater than 10.25V
  2. A/C compressor off for greater than 240 seconds
  3. The following DTCs must not be set: P0531, P0532, P0533, P0606, P0071; P0072; P0073

DTC P0534 Case 1

The difference between the hybrid/EV battery pack coolant outlet temperature and hybrid/EV battery pack coolant inlet temperature within the evaluation period of 120 seconds is less than a calibrated amount of 3 to 5 degrees. The required temperature difference requirement is based on outside air temperature and whether the cabin blower is on or off.

DTC P0534 Case 2

Low side pressure is a less than a designated value based on outside air temperature.

DTC P0534 Case 3

Low side pressure is less than 150 kPa (21.75 PSI) for outside air temperature greater than 5C (41F).

DTC P0534 Case 4

High side pressure is greater than 5000 kPa (725 PSI)

The A/C compressor control module is disabled.

P0534 is a type B DTC.

P1EC3 is the hybrid/EV battery pack heater circuit fault DTC. It diagnoses three different circuit faults (short-ground, short-battery, open circuit); one of these, short to ground, could cause the hybrid/EV battery pack heater to activate and could cause P0534 to set. Diagnose P1EC3 before diagnosing P0534.

  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0537P0538, P153BP0538P0536
Low ReferenceP0538

The A/C refrigerant low side temperature sensor measures the temperature on the low pressure side of the A/C Compressor.

The Hybrid Powertrain control module 2 supplies the A/C evaporator temperature sensor with a low reference circuit and 5-volt signal circuit. The hybrid powertrain control module 2 determines the voltage drop across the sensor, which is proportional to temperature. As the temperature increases, the sensor resistance decreases and the voltage signal decreases. As the temperature decreases, the sensor resistance increases and the voltage signal increases.

  1. DTC P153B makes comparisons between other temperature sensors to determine if the A/C refrigerant low side temperature sensor reading is close to other temperature readings after a soak period. P153B is intended to run after a long ambient soak period, such as being parked overnight, when a hot engine condition has cooled, etc.
  2. DTCs P0537 and P0538 monitor A/C refrigerant low side temperature sensor for out of range conditions.
  3. DTC P0536 looks for the A/C refrigerant low side temperature sensor to go down in temperature when the compressor is operated with a cold engine and after the compressor has been off for one hour.

P0536

  1. 12 V battery system voltage above 10.25 V
  2. Hybrid Powertrain Control Module 2 is awake and communicating.
  3. None of these DTCs may be active: P0537; P0538, P0073; P0072; P0071, P0119; P0118; P0117; P0116, P0606.
  4. Engine coolant temperature must be within 15 degrees of outside air temperature.
  5. AC compressor must have been off for an hour since the last time the AC compressor was on.
  6. AC compressor must be turned on for one minute.

P0537 or P0538

  1. 12 V battery system voltage above 10.25 V
  2. Hybrid Powertrain Control Module 2 is awake and communicating.

P153B

  1. hybrid powertrain control module 2 is awake and communicating.
  2. None of these DTCs may be active: P0537;P0538, P0073; P0072; P0071, P0119; P0118; P0117; P0116, P0531, P0532; P0533, P0606
  3. Outside air temperature raw and corrected values must have had a chance to settle out. Once this occurs these variables are assigned a status of valid. May need to have some time driving in EV mode
  4. Engine coolant temperature must be within 15 degrees of outside air temperature (i.e., cool engine)
  5. Outside air temperature must be between 0°C(32°F) and 55°C(131°F).
  6. AC compressor must have been off for an hour since the last time the AC compressor was on.

P0536

The difference between the A/C refrigerant low side temperature sensor before compressor on and after compressor on changes less than 2 degrees over a 30 second period.

P0537

The hybrid powertrain control module 2 detects the A/C refrigerant low side temperature sensor signal circuit is less than -38°C(-38°F) for more than 15 seconds.

P0538

The hybrid powertrain control module 2 detects the A/C refrigerant low side temperature sensor signal circuit is greater than 85°C(185°F) for more than 4 seconds.

P153B

  1. The difference between the A/C refrigerant low side temperature sensor and the outside air temperature value is greater than 10°C(50°F).
  2. The difference between the A/C refrigerant low side temperature sensor and the temperature calculated from the current high Side Refrigerant Pressure Sensor reading is greater than 10°C(50°F).

These are type B DTCs.

These are type B DTCs.

  1. Vehicle in Service Mode
  2. Verify DTC P0536-P0538 or P153B is not set. If DTC P0536-P0538 or P153B is set Program the K114B hybrid powertrain control module 2. Verify the DTC does not set. If the DTC sets, replace the K114B hybrid powertrain control module 2. If the DTC does not set All OK If DTC P0536-P0538 or P153B is not set
  3. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

Certain performance DTCs in this group, P0D69, P0D71, P076, are intended to run after a long ambient soak period, such as being parked overnight, when a hot engine condition has cooled, etc.

DTC P0D69

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Main HV battery contactors must be closed.
  4. DTCs P0D6A; P0D6B, P0ABC, P0ABD, P0ABB, P0AF8, P1A07, U1111, U185A, P0AE4, P0AD9, P0AA1, P0ADD, P1EBC, P0AE2 must not be set.

DTC P0D6A

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Difference between the A/C compressor control module high voltage levels and the high voltage Battery Pack Side Voltage is less than 15 V.
  4. There are no battery pack voltage DTC's set.
  5. Battery Pack Voltage Sensors are valid.

DTC P0D6B

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Difference between the A/C compressor control module high voltage levels and the high voltage Battery Pack Side Voltage exceeds 15 V.
  4. Battery Pack Voltage Sensors are valid.
  5. There are no battery pack voltage DTC's set.
  6. Main HV Contactors are Closed
  7. No main HV contactor faults are active

DTC P0D6F

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is greater than 0 RPM

DTC P0D71

  1. 12 V battery system voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor has been off for > 6 hours
  4. Outside air temperature is greater than -7°C
  5. Engine coolant temperature is within 15° of outside air temperature
  6. DTCs P0D77, P0D78, P0606 P0073; P0072; P0071, P0113, P0112, P0111, P0114, P0119; P0118; P0117; P0116, P0D72; P0D73 must not be set

DTC P0D72

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Outside Air temperature is greater than -7°C (19°F)
  4. Following DTCs are not set: CPU temp sensor, output driver temp sensor, outside air temperature sensor, engine coolant temperature sensor.

DTC P0D73

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.

DTC P0D76

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Outside Air temperature is greater than -7°C (19°F)
  4. Engine coolant temperature is within 15° of outside air temperature
  5. Compressor has been off for greater than 6 hours
  6. Following DTCs are not set: P0D77; P0D78, P0606, P0073; P0072; P0071, P0073; P0072; P0071, P0113, P0112, P0111, P0114, P0119; P0118; P0117; P0116

DTC P0D77

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Outside Air temperature is greater than -7°C (19°F)
  4. Compressor Speed Request is greater than 0 RPM

DTC P0D78

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.

DTC P0D7A

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D7B

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D7C

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D7D

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D7E

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D7F

  1. 12 V battery system voltage is above 10.25 V.
  2. A/C compressor control module is awake.
  3. Compressor Speed Request is 0 RPM

DTC P0D69

A/C compressor control module high voltage input voltage is not within 10 V of high voltage battery voltage

DTC P0D6A

A/C compressor control module input voltage is greater than 450 V for 6 seconds

DTC P0D6B

A/C compressor control module input voltage is less than 190 V for 6 seconds

DTC P0D6F

A/C compressor control module DC current draw is greater than 27 A for more than 6 seconds.

DTC P0D71

Compressor temperature sensor is not within 10 of intake air temperature sensor and compressor temperature sensor is not within 10° of compressor output driver temperature sensor.

DTC P0D72

less than -40°C (-40°F) for 6 seconds.

DTC P0D73

greater than 135°C (276.6°F) for 6 seconds.

DTC P0D76

Compressor output driver temperature sensor is not within 7° of intake air temperature sensor and compressor output d river temperature sensor is not within 11° of outside air temperature.

DTC P0D77

Air conditioning compressor module output driver temperature sensor is less than -40°C (-40°F)

DTC P0D78

Air conditioning compressor module output driver temperature sensor is greater than 135°C (276.6°F)

DTC P0D7A

Air conditioning compressor motor current U-phase Input greater than or equal to 68 A

DTC P0D7B

Air conditioning compressor motor current U-phase Input less than or equal to -68 A

DTC P0D7C

Air conditioning compressor motor current V-phase Input greater than or equal to 68 A

DTC P0D7D

Air conditioning compressor motor current V-phase Input less than or equal to -68 A

DTC P0D7E

Air conditioning compressor motor current W-phase Input greater than or equal to 68 A

DTC P0D7F

Air conditioning compressor motor current W-phase Input less than or equal to -68 A

The A/C compressor control module is disabled.

These are all type B DTC's

  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

Propulsion system is active.

The coolant heater control module has detected less than 100 V on the high voltage bus for more than 5 seconds.

  1. DTC P0AF8 is a type A DTC.
  2. No cabin heat after 15 seconds.

DTC P0AF8 is a type A DTC.

Do not replace the coolant heater control module based only on DTC P0AF8 being set in history. P0AF8 may be set by disconnecting the high voltage cables to the coolant heater control module and the ignition is turned ON.

WARNINGAlways perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure includes the following steps: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Before working on any high voltage system, be sure to wear the following Personal Protection Equipment: Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors. Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors. Visually and functionally inspect the gloves before use. Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not. Failure to follow the procedures may result in serious injury or death.
WARNINGThe Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center if you have any questions.
  1. Verify that P0AF8 is current and no other DTCs are set. If P0AF8 is history, Do not replace the coolant heater control module. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-487438-S15134519352012072300000) .
  2. P0AF8 is current, Vehicle OFF, disable the high voltage at the K10 coolant heater control module. Refer to «High Voltage Disabling»(ref-487464-S39476959352012072300000) .
  3. Test for less than 10 ohms between the terminals listed below: High voltage DC (-360 V) negative terminal B X4 harness connector at the K114A hybrid powertrain control module 1 to vehicle chassis ground. High voltage DC (+360 V) positive terminal A X4 harness connector at the K114A hybrid powertrain control module 1 to vehicle chassis ground. High voltage DC (+360 V) positive terminal A X4 harness connector at the K114A hybrid powertrain control module 1 and the high voltage DC (-360 V) negative terminal B X4 harness connector at the K114A hybrid powertrain control module 1. High voltage DC (-360 V) negative terminal B X2 harness connector at the K10 coolant heater control module and the high voltage DC (-360 V) negative terminal B X4 harness connector at the K114A hybrid powertrain control module 1. High voltage DC (+360 V) positive terminal A X2 harness connector at the K10 coolant heater control module and the high voltage DC (+360 V) negative terminal A X4 harness connector at the K114A hybrid powertrain control module 1. If greater than the specified range, replace the replace the high voltage DC cables.
  4. If all circuits test normal, and the high voltage DC-360 V circuit fuse is open, replace the K10 coolant heater control module.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0CE0 00, P0CE6 00, P0606 00, P2517 00, P26A6 00, P2681 00P2516 00 P2517 00P0CE7 00, P0606 00, P2518 00, P26A7 00
A/C Low Pressure Sensor SignalP2516 00 P2517 00P2517 00P0CE0 00, P0CE7 00, P0606 00, P2518 00, P26A3 00, P26A9 00P2516 00
Low ReferenceP2517 00

P151C

  1. Vehicle ON
  2. 12 V battery system voltage above 10.25 V.
  3. Hybrid powertrain control module 2 is awake and communicating.
  4. None of these DTCs may be active: P2517, P2518, P0073; P0072; P0071, P0119; P0118; P0117; P0116, P0531, P0532; P0533, P537, P538, P153B, P0606
  5. Outside Air Temperature raw and corrected values must have had a chance to settle out. Once this occurs these variables are assigned a status of valid. May need to have some time driving in EV mode
  6. Engine coolant temperature must be within 15 degrees of outside air temperature
  7. Outside Air Temperature between 0°C (32°F) and 25°C (77°F).
  8. AC compressor must have been off for an hour since the last time the AC compressor was on.

P2516

  1. Vehicle ON
  2. 12 V battery system voltage above 10.25 V.
  3. Hybrid powertrain control module 2 is awake and communicating.
  4. None of these DTCs may be active: P2517, P2518, P0073; P0072; P0071, P0119; P0118; P0117; P0116, P0606
  5. Engine coolant temperature must be within 15 degrees of outside air temperature
  6. AC compressor must have been off for an hour since the last time the AC compressor was on.
  7. AC compressor must be turned on for one minute. (This may the require the service technician to select an HVAC mode that causes the AC compressor to run).

P2517 or P2518

  1. Vehicle ON
  2. 12 V battery system voltage above 10.25 V.
  3. Hybrid powertrain control module 2 is awake and communicating.

DTC P151C

The A/C low side Refrigerant Pressure reading and the A/C high side Refrigerant Pressure reading must be within 200 kPa (29 psi). and the A/C low side Refrigerant Pressure reading and the pressure derived from the A/C Refrigerant Temperature Sensor must be within 200 kPa (29 psi)

DTC P2516

The difference between the A/C low side pressure Sensor before compressor on and after compressor on changes less than 50 kPa (7 psi) over a 15 second period.

DTC P2517

The hybrid powertrain control module 2 detects a short to ground or open at the A/C low side pressure sensor signal circuit.

DTC P2518

The hybrid powertrain control module 2 detects a short to voltage at the A/C low side pressure sensor signal circuit.

These are type B DTCs.

These are type B DTCs.

  1. Vehicle OFF, all vehicle systems OFF, scan tool disconnected, and key removed from vehicle, disconnect the harness connector at the B1C A/C low side 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 Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain 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 K114B hybrid powertrain control module 2. If less than 10 ohms
  3. Vehicle in Service Mode.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground. If less than 4.8 V Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2. Test for infinite resistance between the terminals listed below and ground. Terminal 62 Terminal 63 Terminal 64 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 terminal 63 end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K114B hybrid powertrain control module 2. If greater than 5.2 V Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2 Vehicle in Service Mode. Test for less than 1 V between the terminals listed below and ground. Signal circuit terminal 25 Signal circuit terminal 31 Signal circuit terminal 50 5 V reference circuit terminal 62 5 V reference circuit terminal 63 5 V reference circuit terminal 64 If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K114B hybrid powertrain control module 2. If between 4.8-5.2 V
  5. Verify the scan tool hybrid powertrain control module 2 A/C Low Side Pressure Sensor parameter is less than 0.1 V. If 0.1 V or greater Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2 Vehicle in Service Mode. 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 K114B hybrid powertrain control module 2. If less than 0.1 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 Low Side Pressure Sensor parameter is greater than 4.8 V. If 4.8 V or less Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain 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 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 K114B hybrid powertrain control module 2. If greater than 4.8 V
  8. Test or replace the B1C A/C refrigerant pressure sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

DTC P1ECA

  1. System voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode

DTC P1EC9

  1. System voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor Speed Request is greater than 0 RPM

DTC P1ECA

Sets when the high voltage to the module is greater than 480 V for 3 seconds

DTC P1EC9

Sets when DC Link is above threshold of 60 A for 3 seconds

The A/C compressor control module is disabled but will retry once the compressor speed request goes to 0 RPM and a new speed request greater than 0 RPM is sent.

The DTC can be cleared with the scan tool.

  1. Verify that DTC P1ECA or P1EC9 is not set. If the DTC is set, verify that the A/C compressor control module and the Hybrid/EV powertrain control module 2 have the latest software and reprogram the modules if needed.
  2. Operate the vehicle within the conditions for running the DTC. If the DTC is set, replace the G1 A/C compressor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

DTC P1F0A

  1. 12 V battery system voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor is in start up mode

DTC P1F0B

  1. 12 V battery system voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor is in start up mode

DTC P1F0C

  1. 12 V battery system voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor is in start up mode

DTC P1F0D

  1. 12 V battery system voltage is above 10.25 V.
  2. Vehicle is in Run Mode or Charging Mode
  3. Compressor is in start up mode

DTC P1F0A

  1. A/C compressor control module temperature is greater than 85°C (185°F) and compressor motor speed does not reach to 1800 RPM within 20 seconds after the start of spinning
  2. A/C compressor control module temperature is less than or equal to 85°C and A/C compressor motor speed does not reach to 1800 RPM.

DTC P1F0B

Any A/C compressor control module phase current (U/V/W) greater than or equal to -1A during initial motor startup process

DTC P1F0C

A/C compressor control module DC link Current is less than 2.5 A for 6 seconds

DTC P1F0D

A/C compressor control module DC link Current is greater than 36.7 A for 6 seconds

The A/C compressor control module is disabled but will retry once the compressor speed request goes to 0 RPM and a new speed request greater than 0 RPM is sent.

These are type B DTC's

  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+B046B 00, P26A3 00P26A3 00
5 V ReferenceP0CE0 00, P0CE6 00, P0606 00, P1E00 00, P2517 00, P26A6 00, P2681 00P26A6 00, P2681 00P0CE0 00, P0CE7 00, P0606 00, P1E00, 00, P2518 00, P26A7 00
Coolant Valve Position Sensor SignalP26A6 00P26A7 00P26A7 00
Heater Solenoid Valve ControlP2681 00P2681 00P0CE0 00, P0606 00, P2681 00
Low ReferenceP26A7 00
GroundP0CE0 00

P2681, P26A6 and P26A7

12 V battery system voltage is greater than or equal to 10.25 V.

P26A3 and P26A9

  1. 12 V battery system voltage is greater than or equal to 10.25 V.
  2. The propulsion system is active.
  3. None of the following DTCs are set; P2681, P26A6, P26A7.

P2681

The hybrid powertrain control module 2 has detected a short to voltage or an open on valve drive circuit.

P26A6

The hybrid powertrain control module 2 has detected a short to ground on feedback circuit. The feedback signal is less than 5% (0.25 V).

P26A7

The hybrid powertrain control module 2 has detected a short to voltage on feedback circuit. The feedback signal is greater than 95% (4.25 V).

P26A3

  1. The hybrid powertrain control module 2 has detected a stuck valve.
  2. The valve did not reach the commanded position within 15 seconds after 3 attempts to move the valve.
  3. The coolant temperature is above 50° C. OR
  4. The hybrid powertrain control module 2 has detected a stuck valve.
  5. The valve did not reach the commanded position within 15 seconds
  6. The coolant temperature is above 65° C.

P26A9

  1. The feedback signal is between 70% - 95% (3.5 - 4.75 V) or between 5% - 30% (0.25-1.5 V) OR
  2. The hybrid powertrain control module 2 has detected the valve feedback has drifted beyond acceptable range. OR
  3. The hybrid powertrain control module 2 has detected the valve feedback to be erratic beyond acceptable range.

DTCs P2681, P26A3, P26A6, P26A7 and P26A9 are type B DTCs.

  1. DTCs P2681, P26A3, P26A6, P26A7 and P26A9 are type B DTCs.
  2. DTC P26A3 requires the ignition to cycle from ON to OFF.
  1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the Q66 passenger compartment heater coolant control valve. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the ground circuit terminal 6 and ground. If 5 ohms or greater Vehicle 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 5 ohms
  3. Test for less than 5 ohms between the low reference circuit terminal 5 and ground. If 5 ohms or greater Disconnect the harness connector at the K114B hybrid powertrain 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 K114B hybrid powertrain control module 2. If less than 5 ohms
  4. Vehicle in Service Mode.
  5. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate and the circuit fuse is good Vehicle 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 Vehicle 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 Q66 passenger compartment heater coolant control valve. If the test lamp illuminates
  6. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than 4.8 V Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain 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 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 K114B hybrid powertrain control module 2. If greater than 5.2 V Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode. 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 K114B hybrid powertrain control module 2. If between 4.8-5.2 V
  7. Verify the scan tool Hybrid Powertrain Control Module 2, Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is greater than 95%. If less than 95% Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2. 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 K114B hybrid powertrain control module 2. If greater than 95%
  8. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 5.
  9. Verify the scan tool Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is less than 10%. If 10% or greater Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode. 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 Vehicle 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 K114B hybrid powertrain control module 2. If less than 10%
  10. Verify a test lamp illuminates between the control circuit terminal 2 and the B+ circuit terminal 1 NOTE: It may take up to 5 seconds for illumination to occur. If the test lamp does not illuminate Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode. 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 Vehicle OFF Test for less than 2 ohms on 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 K114B hybrid powertrain control module 2. If the test lamp illuminates
  11. Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2.
  12. Test for infinite resistance between the control circuit terminal 2 and ground. If less than infinite resistance Repair the short to ground on the circuit If infinite resistance
  13. Replace the Q66 passenger compartment heater coolant control valve.
  14. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC. If the DTC sets Replace the K114B hybrid powertrain control module 2. If the DTC does not set
  15. All OK.

Visual/Physical Inspection

  1. Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(ref-487461-S39907746842012072300000) .
  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

HVAC System Malfunction

  1. Perform the «Diagnostic System Check - Vehicle»(ref-487438-S13406627192012072300000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-487438-S08433352102012072300000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-487438-S20414004952012072300000) provides an overview of each diagnostic category.

Check the following mechanical fault sources

  1. Air distribution box
  2. Air distribution hoses/air distribution ducts

An HVAC door stepper motor control circuit fault may cause limited movement on one or all HVAC doors without setting codes. This could cause the following examples of customer concerns.

  1. Air from the HVAC ducts is either not cool or warm enough
  2. There is still some exhaust while in traffic or other outside air noticed when recirculation is requested
  3. Air does not flow from the correct ducts according to what bi-level mode has been chosen on the HVAC display

More articles — HVAC System - Automatic