Home ReviewsRefund
Home/Cadillac/ELR/Cadillac ELR I (2013-2015)/Repair manual/Automatic HVAC System/HVAC System - Automatic
Contents Wiring diagrams Section: Automatic HVAC System All sections

HVAC System - Automatic Cadillac ELR I

Automatic HVAC System 17 illustrations ~21325 words

Sensor Resistance Table

TemperatureAmbient Air Temp SensorInside Air Temp SensorEvaporator Temperature sensor or HVAC Duct temperature SensorsRefrigerant Temperature Sensor
°C°F(K ohms)(K ohms)(K ohms)(K ohms)
4040333.6174.5100.994.3
3531241.1125.172.768.1
3022176.190.753.149.7
2513129.966.539.136.7
20496.849.329.127.3
15572.836.921.820.5
101455.327.916.515.6
52342.321.312.611.9
03232.716.49.79.2
54125.412.77.67.1
105019.9105.95.6
155915.77.94.74.4
206812.56.33.73.5
257710.05.03.02.8
30868.14.02.42.2
35956.53.31.91.8
401045.32.71.51.5
451134.42.21.21.2
501223.61.81.01.0
551313.01.50,80.84
601402.51.20.70.7
651402.11.00.60.58
701581.8.90.50.49
751671.4.80.440.41
801761.2.60.370.35
851851.0.50.320.3

Sensor Resistance Table

Scheme 56

Scheme 56: Power, Ground, Data Communication and Blower Controls
Scheme 56: Power, Ground, Data Communication and Blower Controls

Scheme 57

Scheme 57: Actuators
Scheme 57: Actuators

Scheme 58

Scheme 58: Temperature Sensors
Scheme 58: Temperature Sensors

Scheme 59

Scheme 59: Cabin Heater
Scheme 59: Cabin Heater

Scheme 60

Scheme 60: Compressor Controls
Scheme 60: Compressor Controls

HVAC Component Replacement Reference

Component Code / Schematic NameRepair Instruction Name
M46 Air Recirculation Door ActuatorAir Inlet Valve Actuator Replacement
M6R Air Temperature Door Actuator - RightTemperature Valve Actuator Replacement - Right Side
M6L Air Temperature Door Actuator - LeftTemperature Valve Actuator Replacement - Left Side
M37 Mode Door ActuatorMode Control Cam Actuator Replacement
B7H Air Temperature Sensor - Duct Left UpperDuct Air Temperature Sensor Replacement - Upper Left Side
B7D Air Temperature Sensor - Duct Left LowerDuct Air Temperature Sensor Replacement - Lower Left Side
B7J Air Temperature Sensor - Duct Right UpperDuct Air Temperature Sensor Replacement - Upper Right Side
B7E Air Temperature Sensor - Duct Right LowerDuct Air Temperature Sensor Replacement - Lower Right Side
B39 A/C Evaporator Temperature SensorAir Conditioning Refrigerant Temperature Sensor Replacement
B10B Ambient Light/Sunload SensorSun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement
K8 Blower Motor Control ModuleBlower Motor Control Module Replacement
M8 Blower MotorBlower Motor Replacement
B1 A/C Refrigerant Pressure SensorAir Conditioning Refrigerant Pressure Sensor Replacement - High Pressure
B1C A/C Low Side Pressure SensorAir Conditioning Refrigerant Pressure Sensor Replacement - Low Pressure
B135 Coolant Heater Temperature SensorEngine Coolant Temperature Sensor Replacement - Heater Coolant Heater
Q66 Passenger Compartment Heater Coolant Control Solenoid ValveHeater Water Shutoff Valve Replacement
G36 Auxiliary Coolant PumpHeater Coolant Pump Replacement
K10 Coolant Heater Control ModuleHeater Coolant Heater Replacement
A20 Radio/HVAC ControlsRadio Control Assembly Replacement
K33 HVAC Control ModuleHeater and Air Conditioning Remote Control Replacement

HVAC Component Replacement Reference

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 Performance 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 Performance DTC P0537 Air Conditioning (A/C) Evaporator Temperature Sensor Circuit Low Voltage DTC P0538 Air Conditioning (A/C) Evaporator Temperature Sensor Circuit High Voltage DTC P153B Air Conditioning (A/C) Evaporator Temperature Sensor 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) Refrigerant Low Side Pressure Sensor Not Plausible DTC P2516 Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Performance DTC P2517 Air Conditioning (A/C) Refrigerant Low Side Pressure Sensor Circuit Low Voltage DTC P2518 Air Conditioning (A/C) Refrigerant Low Side 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 P15C5, P2681, P26A3, P26A5-P26A7, or P26A9DTC P15C5 Engine Coolant Bypass Valve Position Sensor Performance - Unexpected Position Change Detected DTC P2681 Engine Coolant Bypass Valve Control Circuit DTC P26A3 Engine Coolant Bypass Valve Performance DTC P26A5 Engine Coolant Bypass Valve Position Sensor 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»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

Circuit/System Description

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

  1. Sun heat intensity
  2. Passenger compartment temperature

The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0-5 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

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

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.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

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/Sunload Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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 air temperature sensors are 2-wire negative temperature co-efficient thermistors. The vehicle uses the following air temperature sensors

  1. Air temperature sensor left upper
  2. Air temperature sensor left lower
  3. Evaporator temperature sensor

A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +85°C (-40 to +185°F). The sensor signal varies between 0-5 V. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease. If the HVAC control module detects a malfunctioning sensor, then the control module software will use a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__sensor-resistance-table) . If not within the specified range Replace the sensor If within the specified range
  4. All OK

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

The windshield temperature and inside moisture sensor integrates the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about

  1. Relative humidity level on inside windshield
  2. Temperature of the inside windshield
  3. Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity on the compartment side of the windshield. It also detects the temperature of the windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient.

  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

  1. Sun heat intensity
  2. Passenger compartment temperature

The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0-5 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

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

  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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/Sunload 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

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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.

The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor speed control from the HVAC control module, battery positive and ground circuits enable the blower motor control module to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the blower motor control module in order to command the blower motor speed. The blower motor control module transfers the PWM signal into a corresponding blower motor voltage. The voltage resides between 2-13 V and changes linear to the height of the PWM signal.

  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

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

With the appropriate switches at the HVAC control, the desired door positions can be selected. The selected values are passed to the HVAC control module via serial data. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the stepper motors with a pulsed ground signal. The stepper motors put the appropriate door into the calculated position in order to reach the desired temperature, mode. and recirculation position.

  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

The auxiliary heater coolant pump is controlled with a pulse-width modulated control sent from the HVAC control module to the auxiliary heater coolant pump. The higher the duty cycle on the control the higher the pump speed. An enable signal from the HVAC control module to the auxiliary heater coolant pump provides overall control of the pump. When voltage is present, the pump can operate. The auxiliary heater coolant pump provides a hard-wired pulse-width modulated feedback signal to the HVAC control module. During normal operation, this feedback signal provides pump speed information.

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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Vehicle in Service Mode, HVAC system turned ON.
  2. Verify the scan tool Auxiliary Heater Coolant Pump Command parameter is between 20%-90%. If the Auxiliary Heater Coolant Pump Command parameter is not between 20%-90%. Refer to Circuit/System Testing If the Auxiliary Heater Coolant Pump Command parameter is between 20%-90%.
  3. Verify the scan tool Auxiliary Heater Coolant Pump Feedback parameter is between 40%-60%. If the Auxiliary Heater Coolant Pump Feedback parameter is not between 40%-60%. Refer to Circuit/System Testing If the Auxiliary Heater Coolant Pump Feedback parameter is between 40%-60%.
  4. All OK
  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 K33 HVAC Control Module 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 K33 HVAC Control Module 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 K33 HVAC Control Module 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 G36 Auxiliary Heater Coolant Pump.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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»(/cadillac/elr/i-2013-2015/remont/testing-diagnostics/#engine-controls-and-fuel-14l-luu-specifications__temperature-versus-resistance) . If not within the specified range Replace the sensor If within the specified range
  4. All OK

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0072P0072P0073P0071
Low ReferenceP0073P0071

The Hybrid/EV Powertrain Control Module 2 supplies the ambient air temperature sensor with a low reference circuit and 5 V signal circuit. The Hybrid/EV Powertrain Control Module 2 determines the voltage drop across the sensor, which is proportional to temperature. As the air temperature increases, the sensor resistance decreases. As the air temperature decreases, the sensor resistance increases.

P0071

  1. The 12 V battery voltage is greater than or equal to 10.2 V.
  2. Ignition switch is not in the CRANK position.
  3. No fault on the air conditioning compressor module.
  4. Hybrid/EV electronics coolant pump off soak time is greater than 1 hour.
  5. Air conditioning compressor module off soak time is greater than 1 hour.
  6. Propulsion system off time is greater than 6 hours.
  7. None of the following DTCs are set; P0111, P0112, P0113, P0114, P0115, P0116, P0117, P0118, P0119, P0CED, P0072, P0073, or U0100.

P0072 and P0073

  1. The ignition is ON
  2. The 12 V battery voltage is greater than or equal to 10.2 V.

P0071

During the first 20 seconds of run time after the 1 hour soaking period, the difference between the outside air temperature and the engine intake air temperature is greater than 30°C(86°F).

P0072

The outside air temperature circuit reference voltage is less than 0.1 V.

P0073

The outside air temperature circuit reference voltage is greater than 0.1 V.

  1. DTC P0071-P0073 are B type DTCs.
  2. The DIC will display SERVICE A/C SYSTEM.
  3. 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 40 fault-free ignition cycles.
  3. DTC P0071-P0073 are B type DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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/EV 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/EV 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/EV 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/EV Powertrain Control Module 2. If greater than 5.2 V Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV 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 K114B Hybrid/EV 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/EV Powertrain Control Module 2 If the DTC does not set
  7. All OK

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Hybrid/EV Powertrain Control Module 2 replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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

The Engine Control Module monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The Engine Control Module supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the Engine Control Module to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the Engine Control Module commands the cooling fans on.

P0531

Engage Test

Compressor speed is greater than 300 RPM.

OFF Test

The compressor has been OFF for more than 20 seconds.

ON Test

The compressor has been ON for more than 10 seconds.

P0532 and P0533

  1. Any of the conditions for setting the DTC are met for 15 seconds.
  2. Battery voltage is between 11-18 V.

P0531

Engage Test

The A/C High Side Pressure sensor change over a predetermined period of time is outside of an acceptable expected amount. The expected amount of change is determined using Ambient Temperature, Coolant Temperature, Vehicle Speed, and Fan Speed.

OFF Test

The A/C High Side Pressure Sensor value is above the acceptable threshold.

ON Test

The A/C High Side Pressure Sensor value is below the acceptable threshold.

P0532

The Engine Control Module detects that the A/C pressure is less than .25 V.

P0533

The Engine Control Module detects that the A/C pressure is greater than 4.75 V.

This is a type B DTC.

This is a type B DTC.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Engine Control Module A/C High Side Pressure Sensor parameter is between .25 V and 4.75 V. If the parameter is not between .25 V and 4.75 V. Refer to Circuit/System Testing. If the parameter is between .25 V and 4.75 V
  3. All OK.
  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.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down and dehumidify the cabin and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High Voltage Battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur

  1. The customer selects ECO or Comfort.
  2. The HVAC system is fan only but the customer selects defrost mode
  3. The High Voltage Battery Thermal System requests the AC compressor on to help maintain the battery temperature

The Hybrid Powertrain control module 2 (HPCM2) uses values from the A/C refrigerant pressure transducers, ambient air temperature sensor, cabin climate control request, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the HPCM2 to the A/C compressor control module via serial data message.

DTC P0534 Case 1

  1. The 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: P1F56, P0CE5, P1F58, P0CE2, P0CE3, P0CE6, P0CE7, P1CE7, P1CE8, P0C47, P0C4A, P1F18, P0C44, P0C45, P0C43, P0CD6, P0CD7, P0CD8, P0071, P0072, P0073.

DTC P0534 Case 2

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

DTC P0534 Case 3

  1. The 12V battery system voltage is equal to or greater than 10.25V.
  2. The AC compressor is on for more than 240 seconds.
  3. Outside air temperature is greater than 5°C (41°F).
  4. The following DTCs must not be set: P2516, P2517, P2518, 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 up to 300 seconds is less than a calibrated amount of 3°C to 5°C 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 less than 150 kPa (21.75 PSI) for outside air temperature greater than 20°C (68°F).

DTC P0534 Case 3

Low side pressure is less than 100 kPa (21.75 PSI) for outside air temperature greater than 5°C (41°F).

Active cooling mode for the battery may be disabled.

P0534 is a type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J43600 ACR Air Conditioning Service Center

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.

The Circuit/System Testing procedure below diagnoses the vehicle for DTC P0534 in the following manner

  1. Verify the A/C pressure sensors are working correctly and the refrigerant charge is correct.
  2. Verify the hybrid/EV battery pack coolant outlet temperature and hybrid/EV battery pack coolant inlet temperature sensors are working correctly and accurately.
  3. Verify the A/C system is operating correctly.
  4. Verify there are no restrictions in the battery cooling system.
  5. Verify the hybrid/EV battery pack coolant control valve is operating correctly.
  6. Verify the drive motor battery coolant cooler is working correctly.
  7. Verify the battery energy control module is working correctly.

A malfunction in any of the systems/components listed above may cause DTC P0534 to set.

  1. Verify that DTC P1EC3, P0C47, P0C4A, P1E8C, P1E8D, or P1F18 is not set. If any of the DTC's are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If the DTC's are not set
  2. Verify that DTC P0534 is not set. If the DTC is set Refer to Circuit/System Testing. If the DTC is not set
  3. All OK.
  1. Install the J43600 ACR Air Conditioning Service Center, vehicle in Service Mode.
  2. Verify the low side pressure reading on the Air Conditioning Service Center is within 3% of the scan tool A/C Low Side Pressure Sensor parameter. If the reading is not within 3% Refer to «DTC P151C or P2516-P2518»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If the reading is within 3%
  3. Verify the high side pressure reading on the Air Conditioning Service Center is within 3% of the scan tool A/C High Side Pressure Sensor parameter. If the reading is not within 3% Refer to «DTC P0531, P0532, or P0533»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If the reading is within 3%
  4. Verify the scan tool Hybrid/EV Battery Pack Coolant Temperature Sensor 1 parameter is within 3% of ambient temperature. If the reading is not within 3% Refer to «DTC P0C43-P0C45»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system) . If the reading is within 3%
  5. Verify the scan tool Hybrid/EV Battery Pack Coolant Temperature Sensor 2 parameter is within 3% of ambient temperature. If the reading is not within 3% Refer to «DTC P0CD6-P0CD8»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system) . If the reading is within 3%
  6. Verify the A/C System is operating correctly, refer to «Air Conditioning (A/C) System Performance Test»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) .
  7. Perform the «Hybrid/EV Battery Pack Coolant Control Valve Learn»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system__hybridev-battery-pack-coolant-control-valve) procedure.
  8. Verify DTC P0CE5, P0CE6, P0CE7, or P1F58 is not set. If DTC P0CE5, P0CE6, P0CE7, or P1F58 is set Refer to «DTC P0CE5-P0CE7 and P1F58»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-battery-heating-and-cooling-system) . If DTC P0CE5, P0CE6, P0CE7, or P1F58 is not set
  9. Command the Q65 Hybrid/EV Battery Pack Coolant Control Valve to 100% Refrigerant/Coolant Heat Exchanger - 0% Bypass with a scan tool.
  10. Disconnect the Q65 Hybrid/EV Battery Pack Coolant Control Valve harness connector.
  11. Vehicle ON, A/C ON.
  12. Command the G37 Hybrid Battery Pack Coolant Pump to 90% with a scan tool.
  13. Verify both the scan tool Hybrid/EV Battery Pack Coolant Temperature Sensor parameters drop at least 8°C (14.5°F) after 20 minutes. If the parameters do not drop at least 8°C (14.5°F) Pinch off or restrict the coolant valve to radiator hose and the coolant valve bypass hose. Verify both the scan tool Hybrid/EV Battery Pack Coolant Temperature Sensor parameters drop at least 8°C (14.5°F) after 20 minutes. If the parameters do not drop at least 8°C (14.5°F), replace the Drive Motor Battery Coolant Cooler. If the parameters drop at least 8°C (14.5°F), replace the Q65 Hybrid/EV Battery Pack Coolant Control Valve. If the parameters drop at least 8°C (14.5°F)
  14. Connect the Q65 Hybrid/EV Battery Pack Coolant Control Valve harness connector.
  15. Clear all codes in the K114B Hybrid Powertrain Control Module 2 using a scan tool.
  16. Verify DTC P0534 does not set while operating the HVAC system under the Conditions for Running the DTC. If the DTC is set Replace the K114B Hybrid Powertrain Control Module 2. If the DTC is not set
  17. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for battery energy control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) 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/EV Powertrain Control Module 2 supplies the A/C evaporator temperature sensor with a low reference circuit and 5-volt signal circuit. The Hybrid/EV 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/EV 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/EV Powertrain Control Module 2 is awake and communicating.

P153B

  1. Hybrid/EV 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/EV 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/EV 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.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Automatic HVAC Description and Operation»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic)
  2. «Heating and Air Conditioning System Description and Operation»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  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/EV Powertrain Control Module 2. Verify the DTC does not set. If the DTC sets, replace the K114B Hybrid/EV Powertrain Control Module 2. If the DTC does not set All OK If DTC P0536-P0538 or P153B is not set
  3. All OK

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Hybrid/EV Powertrain Control Module 2 control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High Voltage Battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur

  1. The customer pushes the AC button
  2. The HVAC control, in AUTO mode, requests the electric AC compressor on to help in cooling the cabin or removing moisture in the defrost mode
  3. The High Voltage Battery Thermal System requests the AC compressor on to help maintain the battery temperature

The Hybrid Powertrain control module 2 uses values from the A/C refrigerant pressure transducers, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, evaporator temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This speed request message is sent from the Hybrid/EV Powertrain Control Module 2 to the A/C compressor control module via serial data message.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

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.
  1. Vehicle in Service Mode
  2. Verify that DTC's P0D69-P0D7F are not set. If any of the DTC's are set Program the G1 A/C compressor control module and the K114B Hybrid/EV powertrain control module 2 with the latest software calibration. Verify the DTC's do not set If any of the DTC's set, replace the affected control module. Refer to «High Voltage Disabling»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system) If none of the DTC's are set All OK If none of the DTC's are set
  3. All OK

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The coolant heater control module will determine when a fault condition is present. Diagnostics and system status are communicated from the coolant heater control module to hybrid powertrain control module 2 through serial data.

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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

For equivalent regional tools, refer to Special Tools .

  1. Verify that DTC P0AF8 is not current and no other DTCs are set. If other DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If DTC P0AF8 is current and no other DTCs are set Refer to Circuit/System Testing If DTC P0AF8 is not current and no other DTCs are set
  2. All OK.
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.
  1. Vehicle OFF, disable the high voltage at the K10 Coolant Heater Control Module. Refer to «High Voltage Disabling»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system) .
  2. Disconnect the X4 harness connector at the T6 Power Inverter Module and disconnect the X2 harness connector at the K10 Coolant Heater Control Module.
  3. Test for infinite resistance between the terminals listed below and ground: K10 Coolant Heater Control Module high voltage DC (-360 V) circuit terminal B X2. K10 Coolant Heater Control Module high voltage DC (+360 V) circuit terminal A X2. If less than infinite resistance Replace the cable assembly. If infinite resistance
  4. Test for infinite resistance between the K10 Coolant Heater Control Module high voltage DC (+360 V) terminal A X2 and the K10 Coolant Heater Control Module high voltage DC (-360 V) circuit terminal B X2. If less than infinite resistance Replace the cable assembly. If less than infinite resistance
  5. Verify the high voltage DC-360 V circuit fuse is not open. If the high voltage DC-360 V circuit fuse is open Replace the K10 Coolant Heater Control Module. If the high voltage DC-360 V circuit fuse is not open
  6. Test for less than 10 ohms between the following terminals listed below: K10 Coolant Heater Control Module high voltage DC (+360 V) circuit terminal A X2 and the T6 Power Inverter Module high voltage DC (+360 V) circuit terminal A X4. K10 Coolant Heater Control Module high voltage DC (-360 V) circuit terminal B X2 and the T6 Power Inverter Module high voltage DC (-360 V) circuit terminal B X4. If 10 ohms or greater Replace the cable assembly. If less than 10 ohms
  7. Replace the T6 Power Inverter Module.
  8. Verify that DTC P0AF8 does not set while operating the vehicle system under the Conditions for Running the DTC. If DTC P0AF8 is set Replace the K10 Coolant Heater Control Module. If DTC P0AF8 does not set
  9. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-APM Module)»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system) , «300-Volt Battery Positive and Negative Cable Replacement (Inverter-to-Compressor/Heater Module)»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system) , «300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Charger)»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system) , «300-Volt Battery Positive and Negative Cable Replacement (Drive Motor Battery-to-Inverter)»(/cadillac/elr/i-2013-2015/remont/body-electrical/#hybridev-energy-storage-system)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for coolant heater control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0CE5 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 00P0CE5 00, P0CE7 00, P0606 00, P2518 00, P26A5 00, P26A9 00P2516 00
Low ReferenceP2517 00

The Hybrid/EV Powertrain Control Module 2 monitors the low side refrigerant pressure through the A/C pressure sensor. The Hybrid/EV Powertrain Control Module 2 supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the Hybrid/EV Powertrain Control Module 2 to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low.

P151C

  1. Vehicle ON
  2. 12 V battery system voltage above 10.25 V.
  3. Hybrid/EV 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.
  9. High side refrigerant pressure reading must be between 0 kPa and 675 kPa.

P2516

  1. Vehicle ON
  2. 12 V battery system voltage above 10.25 V.
  3. Hybrid/EV 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 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/EV Powertrain Control Module 2 is awake and communicating.

DTC P151C

  1. The A/C low side Refrigerant Pressure reading and the A/C high side Refrigerant Pressure reading differ by more than 200 kPa (29 psi).
  2. Loss of HVAC Control Module communication

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/EV 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/EV 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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify that DTCs U0140 and U184B are not set. If any of the DTCs are set Refer to «DTC U0100-U02FF»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-dtc-b1000-to-dtc-u183c) , or «DTC U184B»(/cadillac/elr/i-2013-2015/remont/communication-devices/#data-communication-system-dtc-u183e-to-dtc-u2612-and-diagnostic-information-and-procedures) . If none of the DTCs are set
  3. Refer to Circuit/System Testing.
  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/EV 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/EV 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/EV 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/EV Powertrain Control Module 2. If greater than 5.2 V Vehicle OFF, disconnect the harness connector at the K114B Hybrid/EV 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/EV Powertrain Control Module 2. If between 4.8-5.2 V
  5. Verify the scan tool Hybrid/EV 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/EV 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/EV 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/EV 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/EV Powertrain Control Module 2. If greater than 4.8 V
  8. Test or replace the B1C A/C Low Side Pressure Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The A/C compressor function is to provide refrigerant flow in the A/C refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High Voltage Battery and inverts it to alternating current for the motor. The A/C compressor shall be activated when any of the three following events occur

  1. The customer pushes the AC button
  2. The HVAC control, in AUTO mode, requests the electric A/C compressor on to help in cooling the cabin or removing moisture in the defrost mode
  3. The High Voltage Battery Thermal System requests the A/C compressor on to help maintain the battery temperature

The Hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure transducers, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, evaporator temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This speed request message is sent from the Hybrid/EV powertrain control module 2 to the A/C compressor control module via GM LAN message.

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 s

DTC P1EC9

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

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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify DTC P1ECA or P1EC9 is not set. If either DTC is set Program the G1 A/C Compressor and the K114B Hybrid/EV Powertrain Control Module 2 with the latest software calibration. Verify DTC P1ECA or P1EC9 is not set. If either DTC is set, replace the G1 A/C Compressor. If the DTCs are not set All OK. If the DTCs are not set
  2. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Hybrid/EV powertrain control module 2 replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The A/C compressor function is to provide refrigerant flow in the A/C refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes High Voltage direct current from the vehicle's High voltage battery and inverts it to alternating current for the motor. The A/C compressor shall be activated when any of the three following events occur

  1. The customer pushes the AC button
  2. The HVAC control, in AUTO mode, requests the electric A/C compressor on to help in cooling the cabin or removing moisture in the defrost mode
  3. The High Voltage Battery Thermal System requests the A/C compressor on to help maintain the battery temperature

The Hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure transducers, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, evaporator temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the Hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.

A/C Compressor has a motor start up procedure that can take a variable length of time to run to bring the motor up to requested speed. Length of time is dependent on external conditions such as underhood temperature and high side pressure. In hotter conditions, the motor start up time will be longer. The A/C compressor control module monitors an internal parameter known as the DC link current which is based off DC input current. It is not possible to measure this parameter externally.

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 s 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 -1 A during initial motor startup process

DTC P1F0C

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

DTC P1F0D

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

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify that DTCs P0F0A-P1F0D are not set. If any of the DTCs are set Program the G1 A/C Compressor and the K114B Hybrid/EV Powertrain Control Module 2 with the latest software calibration. Verify the DTCs do not set If any of the DTCs set, replace the affected control module. If none of the DTCs are set All OK. If none of the DTCs are set
  3. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Hybrid/EV powertrain control module 2 replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+B046B 00, P26A5 00P26A5 00
5 V ReferenceP0CE5 00, P0CE6 00, P0606 00, P1E00 00, P2517 00, P26A6 00, P2681 00P26A6 00, P2681 00P0CE5 00, P0CE7 00, P0606 00, P1E00, 00, P2518 00, P26A7 00
Coolant Valve Position Sensor SignalP26A5 00, P26A6 00P26A5 00, P26A7 00P26A5 00, P26A7 00
Heater Solenoid Valve ControlP2681 00P2681 00P0CE5 00, P0606 00, P2681 00
Low ReferenceP26A7 00
GroundP0CE5 00

The passenger compartment heater coolant control valve regulates the engine coolant flow into the cabin heater loop depending on engine coolant temperature and ambient temperature conditions. The passenger compartment heater coolant control valve has two positions: ByPass or Link. In the ByPass position, the coolant in the engine loop and heater loop are separated and in the link position the coolant circulates through both loops. The valve movement is controlled by a PWM signal. A 50% duty cycle is a normal duty cycle. A 75% duty cycle represents a valve commanded to the link position. A 25% duty cycle represents a valve commanded to the ByPass position. The passenger compartment heater coolant control valve uses an internal position sensor that sends a signal to the hybrid powertrain control module 2 to determine the valve position.

When the engine coolant temperature heats up, a valve learn procedure takes place. The hybrid powertrain control module 2 commands the valve to the link position and records the voltage coming back from the position sensor. Then the hybrid powertrain control module 2 commands the valve back to the bypass position and records the voltage coming back from the position sensor. The voltage values in both the link and bypass positions must fall within calibrated ranges.

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 coolant temperature is above 50°C(122°F).
  3. The propulsion system is active.
  4. None of the following DTCs are set; P0116, P0117, P0118, P0119, P2681, P26A6, P26A7.

P15C5 and P26A5

  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 and P26A5

  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(122°F). 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(149°F).

P26A9

  1. The feedback signal is between 70% - 95% (3.5 - 4.75 V) or between 5% - 30% (0.25-1.5 V)

P15C5

  1. The hybrid powertrain control module 2 has detected the valve feedback has drifted beyond acceptable range.

DTCs P15C5, P2681, P26A3, P26A5, P26A6, P26A7 and P26A9 are type B DTCs.

  1. DTCs P15C5, P2681, P26A3, P26A5, P26A6, P26A7 and P26A9 are type B DTCs.
  2. DTC P26A9 requires the ignition to cycle from ON to OFF and coolant temperature is above 50°C(122°F).

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify that DTC P0606, P0CE7, P2518 or P26A7 is not set. If any of the DTCs are set Refer to «DTC P151C or P2516-P2518»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If none of the DTCs are set
  3. Refer to Circuit/System testing.
  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 min 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/EV 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/EV 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, remove the test lamp. 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, remove the test lamp. 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. Remove the test lamp.
  7. 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/EV 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/EV Powertrain Control Module 2. If greater than 5.2 V Vehicle OFF, disconnect the X1 harness connector at the K114B Hybrid/EV 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/EV Powertrain Control Module 2. If between 4.8-5.2 V
  8. 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/EV 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/EV Powertrain Control Module 2. If greater than 95%
  9. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 5.
  10. Verify the scan tool Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is less than 10%. If 10% or greater Vehicle OFF, remove the jumper wire and disconnect the harness connector at the K114B Hybrid/EV 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/EV Powertrain Control Module 2. If less than 10%
  11. Remove the jumper wire.
  12. 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, remove the test lamp and disconnect the harness connector at the K114B Hybrid/EV 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/EV Powertrain Control Module 2. If the test lamp illuminates
  13. Vehicle OFF, remove the test lamp and disconnect the harness connector at the K114B Hybrid/EV Powertrain Control Module 2.
  14. 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
  15. Replace the Q66 Passenger Compartment Heater Coolant Control Valve.
  16. 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/EV Powertrain Control Module 2. If the DTC does not set
  17. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Heater Water Shutoff Valve Replacement»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for the K114B Hybrid/EV Powertrain Control Module 2 replacement, programming and setup

Symptoms - HVAC Systems - Automatic

Note. The following steps must be completed before using the symptom tables

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Automatic HVAC Description and Operation»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  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

Intermittent

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

Symptom List

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

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/elr/i-2013-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The heating and cooling system is controlled through the radio/HVAC controls faceplate interface. The HVAC control module receives a serial data message from the faceplate when the user chooses an HVAC function change. The HVAC module, hybrid powertrain control module 2, and engine control module (ECM) all interface via serial data and use inputs from air, refrigerant, coolant, and moisture temperature sensors, refrigerant pressure sensors, the sunload sensor, and the moisture sensors. This information is used to determine the optimal output for the passenger compartment coolant bypass valve, coolant heater, heater coolant pump, mode door, temperature door, recirculation door, and blower motor.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/elr/i-2013-2015/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Vehicle in Service Mode.
  2. Verify the scan tool Blower Motor Switch parameter changes when pressing the switch If the parameter does not change Replace the A20 radio/HVAC controls If the parameter changes
  3. Verify that the blower motor operates properly with the blower motor switch in each speed position. If the blower motor does not operate in each speed position Refer to «DTC B0193»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If the blower motor operates properly in each speed position.
  4. Verify the scan tool parameters listed below change when pressing the appropriate switch. Left Temperature Switch Air Recirculation Mode Switch Bi-Level Switch If any parameter does not change Replace the A20 radio/HVAC controls If all parameters change
  5. Vehicle ON, HVAC in comfort mode.
  6. Verify the HVAC modes listed below change when pressing the appropriate switch. Temperature Bi-Level Mode Recirculation If any HVAC mode does not change Refer to «DTC B0223, B0233, B023A, or B0408»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If all HVAC modes change
  7. Verify cool air flows from the ducts with the temperature control in the coldest position. If the air is not cool Refer to «Air Conditioning (A/C) System Performance Test»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) . If the air is cool
  8. Verify warm air flows from the ducts with the temperature control in the warmest position. If the air is not warm Refer to «Heating Performance Diagnostic»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__heating-performance-diagnostic) . If the air is warm
  9. Vehicle in Service Mode
  10. Verify the scan tool Sunload parameter changes, while covering the B10B ambient light sunload sensor with a shop towel or other suitable item. If the Sunload parameter does not change Refer to «DTC B0183»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If the Sunload parameter changes
  11. Verify the actual inside air temperature, using a thermometer, is less than 3°C (5°F) difference from the scan tool Inside Passenger Compartment Air Temperature parameter. If greater than a 3°C (5°F) difference Refer to «DTC B0163»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If less than a 3°C (5°F) difference
  12. Verify the scan tool parameters listed below are less than 3°C (5°F) of the actual duct temperature. Lower Left Duct Air Temperature Upper Left Duct Air Temperature If 3°C (5°F) or greater Refer to «DTC B0173, B0178, or B3933»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If less than 3°C (5°F)
  13. Vehicle ON and A/C ON.
  14. Verify the scan tool A/C Evaporator Temperature parameter is between -35°C (-39°F) and 85°C (185°F) and changes as the evaporator air temperature changes. If the parameter is not between -35°C (-39°F) and 85°C (185°F) Refer to «DTC P0536-P0538 or P153B»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic) . If the parameter is between -35°C (-39°F) and 85°C (185°F).
  15. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «HVAC Component Replacement Reference»(/cadillac/elr/i-2013-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
  2. «Control Module References»(/cadillac/elr/i-2013-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module and radio/HVAC control replacement, programming and setup

Afterblow Enabling

The afterblow mode can be enabled using the scan tool. The afterblow mode allows the blower motor to operate after the engine has been turned off. This operation of the blower motor dries the evaporator core, which reduces the amount of microbial growth which can create undesirable odors.

Use the following procedure in order to enable the afterblow mode

  1. Connect the Scan Tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Build the vehicle with the scan tool.
  4. Select Module Diagnosis.
  5. Select Remote Heater and Air Conditioning Control Module.
  6. Select Configuration/Reset Functions.
  7. Select HVAC Afterblow Configuration.

When afterblow has been enabled by the scan tool the blower motor will operate at 68% blower speed, following the sequence below up to 5 times. This could last up to an hour

  1. The blower motor will be OFF for 7-11 minutes.
  2. The blower motor will RUN for 25-30 seconds.

The following conditions must be met for the HVAC module to operate the afterblow

  1. The engine must be turned off for at least 30 min.
  2. The outside air temperature must be at least 21°C (70°F).
  3. The A/C compressor must have operated for more than 2 minutes before shut down during the latest key cycle.
  4. The system voltage must be at least 12 V.

Actuator Recalibration

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

When replacing the HVAC control module it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC control module be sure to perform the following

  1. Place the ignition switch to the OFF position.
  2. Disconnect the scan tool.
  3. Install the HVAC control module.
  4. Connect all previously disconnected components.
  5. Vehicle in Service Mode.
  6. Wait 40 seconds for the HVAC control module to self-calibrate.
  7. Verify that no DTCs have set as current DTCs.

When replacing the HVAC actuator it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC actuator be sure to perform one of the following

Preferred Method (with Scan Tool)

  1. Clear all DTCs.
  2. Place the ignition switch in the OFF position.
  3. Install the HVAC actuator.
  4. Connect all previously disconnected components.
  5. Start the vehicle.
  6. With the scan tool, initiate the HVAC Actuators re-calibration feature of the Remote Heater and Air Conditioning Control Module Special Functions menu.
  7. Verify that no DTCs have set as current DTCs.

Alternate Method (without Scan Tool)

  1. Clear all DTCs.
  2. Place the ignition switch to the OFF position.
  3. Install the HVAC actuator.
  4. Connect all previously disconnected components.
  5. Remove the HVAC control module fuse for a minimum of 10 seconds.
  6. Install the HVAC control module fuse.
  7. Vehicle in Service Mode.
  8. Wait 40 seconds for the HVAC control module to self-calibrate.
  9. Verify that no DTCs have set as current DTCs.

Scheme 61

Scheme 61: Heater and Air Conditioning Remote Control Replacement
Scheme 61: Heater and Air Conditioning Remote Control Replacement
Call outComponent Name
Preliminary Procedure Remove the radio control assembly. Refer to Radio Control Assembly Replacement .
1Heater And Air Conditioning Remote Control Module Procedures Disconnect the heater and air conditioning remote control module electrical connectors. Perform the HVAC system control module programming and setup procedure. Refer to HVAC System Control Module Programming and Setup . Perform the actuator re-calibration procedure. Refer to Actuator Recalibration .

Heater and Air Conditioning Remote Control Replacement

Scheme 62

Scheme 62: Air Conditioning Module Wiring Harness Replacement
Scheme 62: Air Conditioning Module Wiring Harness Replacement
Call outComponent Name
Preliminary Procedures Remove the heater and air conditioning remote control. Refer to Heater and Air Conditioning Remote Control Replacement . Remove the instrument panel compartment. Refer to Instrument Panel Compartment Replacement . Remove the left side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Left Side . Remove the instrument panel knee bolster. Refer to Instrument Panel Knee Bolster Replacement . Remove the right side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Right Side .
1Air Conditioning Module Wiring Harness Procedures Disconnect the duct air temperature sensor electrical connectors. Disconnect the temperature valve actuator electrical connectors. Disconnect the air inlet valve actuator electrical connector. Un-clip the air conditioning module wiring harness from the heater and air conditioning evaporator and blower module. Maneuver the air conditioning module wiring harness out from behind the instrument panel, and out through the center dash area. Perform the actuator re-calibration procedure. Refer to Actuator Recalibration .

Air Conditioning Module Wiring Harness Replacement

Scheme 63

Scheme 63: Air Inlet Valve Actuator Replacement
Scheme 63: Air Inlet Valve Actuator Replacement
Call outComponent Name
Preliminary Procedure Remove the air inlet valve actuator gear. Refer to Air Inlet Valve Actuator Gear Replacement .
1Air Inlet Valve Actuator Fasteners (Qty: 3) CAUTION: Refer to Fastener Caution .
2Air Inlet Valve Actuator Procedures Disconnect the air inlet valve actuator electrical connector. Perform the actuator calibration procedure. Refer to Actuator Recalibration .
CAUTION
Refer to Fastener Caution .

Air Inlet Valve Actuator Replacement

Scheme 64

Scheme 64: Mode Control Cam Actuator Replacement
Scheme 64: Mode Control Cam Actuator Replacement
Call outComponent Name
Preliminary Procedure Remove the brake pedal assembly. Refer to Brake Pedal Assembly Replacement .
1Mode Control Cam Actuator Fastener (Qty: 3) CAUTION: Refer to Fastener Caution .
2Mode Control Cam Actuator Assembly Procedures Disconnect the mode control cam actuator electrical connector. Perform the actuator calibration procedure. Refer to Actuator Recalibration .
CAUTION
Refer to Fastener Caution .

Mode Control Cam Actuator Replacement

Scheme 65

Scheme 65: Temperature Valve Actuator Replacement - Right Side
Scheme 65: Temperature Valve Actuator Replacement - Right Side
Call outComponent Name
Preliminary Procedures Remove the instrument panel compartment assembly. Refer to Instrument Panel Compartment Replacement . Remove the right side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Right Side .
1Right Side Temperature Valve Actuator Fastener (Qty: 2) CAUTION: Refer to Fastener Caution .
2Temperature Valve Actuator - Right Side Procedures Disconnect the right side temperature valve actuator electrical connector. Perform the actuator calibration procedure. Refer to Actuator Recalibration .
CAUTION
Refer to Fastener Caution .

Temperature Valve Actuator Replacement - Right Side

Temperature Valve Actuator Replacement - Left Side

Call outComponent Name
Preliminary Procedures Remove the instrument panel knee bolster. Refer to Instrument Panel Knee Bolster Replacement . Remove the left side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Left Side .
1Left Side Temperature Valve Actuator Fastener (Qty: 2) CAUTION: Refer to Fastener Caution .
2Temperature Valve Actuator - Left Side Procedures Disconnect the left side temperature valve actuator electrical connector. Perform the actuator calibration procedure. Refer to Actuator Recalibration .
CAUTION
Refer to Fastener Caution .

Temperature Valve Actuator Replacement - Left Side

Scheme 66

Scheme 66: Air Conditioning Refrigerant Temperature Sensor Replacement
Scheme 66: Air Conditioning Refrigerant Temperature Sensor Replacement
Call outComponent Name
Preliminary Procedure Remove the right front floor air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Right Side .
1Air Conditioning Refrigerant Temperature Sensor Procedures Disconnect the air conditioning refrigerant temperature sensor electrical connector. To remove the air conditioning refrigerant temperature sensor, turn the air conditioning refrigerant temperature sensor counter clock wise a quarter of a turn.

Air Conditioning Refrigerant Temperature Sensor Replacement

Scheme 67

Scheme 67: Duct Air Temperature Sensor Replacement - Upper Right Side
Scheme 67: Duct Air Temperature Sensor Replacement - Upper Right Side
Call outComponent Name
Preliminary Procedures Remove the instrument panel air bag assembly. Refer to Instrument Panel Airbag Replacement . Reposition the dash wiring harness to gain access to the upper right side duct air temperature sensor.
1Duct Air Temperature Sensor - Upper Right Side Procedures Disconnect the upper right side duct air temperature sensor electrical connector. To remove the upper right side duct air temperature sensor, turn the upper right side duct air temperature sensor counter clock wise a quarter of a turn.

Duct Air Temperature Sensor Replacement - Upper Right Side

Scheme 68

Scheme 68: Duct Air Temperature Sensor Replacement - Upper Left Side
Scheme 68: Duct Air Temperature Sensor Replacement - Upper Left Side
Call outComponent Name
Preliminary Procedures Remove the instrument cluster assembly. Refer to Instrument Cluster Replacement . Reposition the dash wiring harness to gain access to the upper left side duct air temperature sensor.
1Duct Air Temperature Sensor - Upper Left Side Procedures Disconnect the upper left side duct air temperature sensor electrical connector. To remove the upper left side duct air temperature sensor, turn the upper left side duct air temperature sensor counter clock wise a quarter of a turn.

Duct Air Temperature Sensor Replacement - Upper Left Side

Scheme 69

Scheme 69: Duct Air Temperature Sensor Replacement - Lower Left Side
Scheme 69: Duct Air Temperature Sensor Replacement - Lower Left Side
Call outComponent Name
Preliminary Procedures Remove the instrument panel knee bolster. Refer to Instrument Panel Knee Bolster Replacement . Remove the left side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Left Side .
1Duct Air Temperature Sensor - Lower Left Side Procedures Disconnect the lower left side duct air temperature sensor electrical connector. To remove the lower left side duct air temperature sensor, turn the lower left side duct air temperature sensor counter clock wise a quarter of a turn.

Duct Air Temperature Sensor Replacement - Lower Left Side

Scheme 70

Scheme 70: Duct Air Temperature Sensor Replacement - Lower Right Side
Scheme 70: Duct Air Temperature Sensor Replacement - Lower Right Side
Call outComponent Name
Preliminary Procedures Remove the instrument panel compartment assembly. Refer to Instrument Panel Compartment Replacement . Remove the right side floor front air outlet duct. Refer to Floor Front Air Outlet Duct Replacement - Right Side .
1Duct Air Temperature Sensor - Lower Right Side Procedures Disconnect the lower right side duct air temperature sensor electrical connector. To remove the lower right side duct air temperature sensor, turn the lower right side duct air temperature sensor counter clock wise a quarter of a turn.

Duct Air Temperature Sensor Replacement - Lower Right Side

Scheme 71

Scheme 71: Windshield Outside Moisture/Ambient Light and Humidity Sensor Replacement
Scheme 71: Windshield Outside Moisture/Ambient Light and Humidity Sensor Replacement
Call outComponent Name
Preliminary Procedure Remove the inside rearview mirror wiring harness lower cover. Refer to Inside Rearview Mirror Wiring Harness Lower Cover Replacement .
1Windshield Outside Moisture and Ambient Light and Humidity Sensor Procedure Unlatch the windshield outside moisture and ambient light and humidity sensor from under the multi-function relay module bracket clip. Disconnect the windshield outside moisture and ambient light and humidity sensor electrical connector.

Windshield Outside Moisture/Ambient Light and Humidity Sensor Replacement

Scheme 72

Scheme 72: Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement
Scheme 72: Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement
Call outComponent Name
Preliminary Procedure Remove the instrument panel extension. Refer to Instrument Panel Extension Replacement .
1Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Procedures Disconnect the electrical sun load temperature and headlamp automatic control ambient light sensor connector. Turn the sun load temperature and headlamp automatic control ambient light sensor a quarter of a turn counter clockwise to remove.

Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement

HVAC Control Components

HVAC Control

The HVAC control contains all switches, which are required to control the functions of HVAC and serve as interface between the operator and the HVAC control module. The selected values are passed to the HVAC control module via serial data.

HVAC Remote Control Module

The HVAC control module is a serial data device that interfaces between the operator and the HVAC system to maintain and control desired air temperature and air distribution settings. The battery positive voltage circuit provides power that the HVAC control module uses for keep alive memory. If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from keep alive memory. The body control module (BCM), which is the vehicle power mode master, provides a device ON-Signal. The HVAC control module provides blower, air delivery mode and air temperature settings.

The HVAC control module supports the following features

FeatureAvailability
PurgeYes
PersonalizationYes
Actuator CalibrationYes

HVAC Coolant Pump

The HVAC control module will control a cabin coolant heater pump based on a valid flow rate. If the HVAC Heating system requests a coolant flow rate, the HVAC coolant pump will be commanded "on" and to the desired speed.

HVAC Cabin Coolant Sensor

The HVAC control module will monitor a coolant temperature sensor input. This will be used to determine the heat source requirements for the coolant heater control module. This input will also be used along with engine temperature and other vehicle inputs.

Mode Actuator

The mode actuator is a 5-pin stepper motor. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor puts the mode flap into the calculated position in order to reach the selected position. The null point of the stepper motor will be calibrated, if the stepper motor is new. When the stepper motor is calibrated, the HVAC control module can drive the applicable coil to reach exactly the desired position of the flap.

Air Temperature Actuator

The air temperature actuator is a 5-pin stepper motor. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor puts the mixed air flap into the calculated position, in order to reach the selected temperature. The null point of the stepper motor will be calibrated, if the stepper motor is new. When the stepper motor is calibrated, the HVAC control module can drive the applicable coil to reach exactly the desired position of the flap.

Recirculation Actuator

The recirculation actuator is a 5-pin stepper motor. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor puts the recirculation flap into the calculated position in order to reach the desired position. The null point of the stepper motor will be calibrated, if the stepper motor is new. When the stepper motor is calibrated, the HVAC control module can drive the applicable coil to reach exactly the desired position of the flap.

Blower Motor Control Module

The blower motor control module controls the speed of the blower motor by increasing or decreasing the voltage drop on the ground side of the blower motor. The HVAC control module provides a low side pulse width modulation (PWM) signal to the blower motor control module via the blower motor speed control circuit. As the requested blower speed increases, the HVAC control module increases the amount of time that the speed signal is modulated to ground. As the requested blower speed decreases, the HVAC control module decreases the amount of time that the signal is modulated to ground.

Duct Temperature Sensors

The air temperature sensors are 2-wire negative temperature co-efficient thermistors. The sensors operate within a temperature range of -40 to +85°C (-40 to +185°F). The sensors are installed in the air distribution ducts and measure the temperature of the air that streams from the ducts. The HVAC control module uses these values to calculate the mixed air flap position.

Evaporator Temperature Sensor

The evaporator temperature sensor is a 2-wire negative temperature co-efficient thermistor. The sensor operates within a temperature range of -40 to +85°C (-40 to +185°F). The sensor is installed at the evaporator and measures its temperature. If the temperature drops close to 3°C (38°F), the A/C compressor will be commanded off by the HVAC control module in order to prevent icing of the evaporator.

A/C Refrigerant Temperature Sensor

The A/C refrigerant temperature sensor is a 2-wire negative temperature co-efficient thermistor. The sensor operates within a temperature range of -40 to +85°C (-40 to +185°F). The sensor is installed in the low side refrigerant line and measures its temperature. If the temperature drops close to 3°C (38°F), the A/C compressor will be commanded off by the Hybrid/EV powertrain control module 2 in order to prevent icing of the evaporator.

Windshield Temperature and Inside Moisture Sensor

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about

  1. Relative humidity level at windshield (compartment side)
  2. Temperature of the windshield inside (compartment side)
  3. Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the passenger compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element.

Ambient Light/Sunload Sensor

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

  1. Sun heat intensity
  2. Passenger compartment temperature

The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4-4.5 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

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

A/C Compressor

The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes high voltage direct current from the vehicle's high voltage battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur

  1. The customer pushes the AC button or
  2. The HVAC control, in ECO climate or Comfort Climate Settings, requests the electric AC compressor on to help in cooling the cabin or removing moisture in conditions where the windows may fog or
  3. The hybrid/EV powertrain control module 2 requests the AC compressor on to help maintain the battery temperature

The hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure sensor, A/C refrigerant thermistor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, evaporator temperature sensor, battery cell temperature sensors, battery coolant temperature sensors and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.

Air Speed

The blower control switch is part of the HVAC faceplate control. The selected value of the blower switch position is sent to the HVAC control module via serial data.

The blower motor control module is an interface between HVAC control module and blower motor. The blower motor control module regulates supply voltage and ground circuits to blower motor. The HVAC control module provides a PWM signal to the blower motor control module in order to command the desired blower motor speed. The blower motor control module supplies battery voltage to the blower motor and uses the blower motor ground as a low side control to adjust the blower motor speed. The voltage amounts between 2-13 V and changes linear to the height of the PWM signal.

Afterblow

Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned OFF. This reduces the amount of microbial growth that can create undesirable odors. The vehicle does not come equipped with the afterblow feature turned ON. If the afterblow feature is required due to an odor concern, it must be enabled using the scan tool Afterblow configuration function.

After the HVAC control module has been programmed for afterblow, the following conditions must be met for afterblow to operate

  1. The engine has been turned OFF for at least 30 minutes.
  2. The ambient air temperature is at least 21°C (70°F).
  3. The A/C compressor operated for more than 2 minutes before shut down.
  4. The system voltage is at least 12 volts.

Once the above conditions have been met, the following sequence of events will occur

  1. The blower motor will RUN for 20 seconds.
  2. The blower motor will be OFF for 10 minutes.
  3. The blower motor will RUN for and additional 20 seconds.

Air Delivery

The HVAC control module controls the distribution of air within the passenger compartment by the use of the mode actuator. The modes that may be selected are

  1. Defrost
  2. Defog
  3. Panel
  4. Floor
  5. BiLevel

In auto mode, the air delivery mode is controlled automatically based on cooling/warming needs of the compartment. The desired air distribution mode can be selected with the air distribution buttons at the HVAC faceplate control. The HVAC control delivers the values to the HVAC control module via serial data. The HVAC control module controls the mode actuator so that it drives the flap to the calculated position. Depending on the position of the flap, air is distributed through various ducts leading to the outlets in the dash. Turning the mode flap to the defrost position, the HVAC control module will move the recirculation actuator to outside air, reducing window fogging. When defrost is selected, the blower motor will be activated. The HVAC control module enables a high volume of air delivered to the front defrost vents. A/C is available in all modes.

The rear window defogger does not affect the HVAC system.

Heating and A/C Operation

The purpose of the heating and A/C system is to provide heated and cooled air to the interior of the vehicle. The A/C system will also remove humidity from the interior and reduce windshield fogging. Regardless of the temperature setting, the following can affect the rate that the HVAC system can achieve the desired temperature

  1. Ambient air temperature
  2. Difference between inside and desired temperature
  3. Blower motor speed setting
  4. Mode setting
  5. Air conditioning control module operation
  6. Hybrid/EV powertrain control module 2 operation
  7. Coolant heater control module

Pressing the climate mode buttons (Comfort Mode or ECO Mode) enables the HVAC control module to determine whether to request A/C compressor and coolant heater activation. Based on the thermal conditions of the vehicle the HVAC control module sends a serial data message to the hybrid/EV powertrain control module 2 for the A/C request. The hybrid/EV powertrain control module 2 will request the A/C compressor control Module to engage A/C. The HVAC control module sends the heating request to the coolant heater control module to produce heat.

Climate Mode button (Fan Only) will disable all heating and cooling of the vehicle unless overridden by dehumidification requirements.

Recirculation Operation

The recirculation button is part of the HVAC faceplate control. The selected recirculation button position is sent to the HVAC control module via serial data. The HVAC control module controls the air intake through the recirculation actuator. The recirculation switch closes and opens the recirculation flap in order to circulate the air within the vehicle, or route outside air into the vehicle.

Inside air recirculation is prevented if the defrost mode is not active. When the defrost mode is active, the recirculation actuator opens the recirculation flap and outside air is circulated to the windshield to reduce fogging.

In automatic recirculation mode the values of the windshield temperature and inside moisture sensor are used as control inputs for the HVAC control module application to calculate the fog risk on the passenger compartment side of the windshield. The A/C compressor and the defrost mode are activated to prevent or remove fog on the passenger compartment side of the windshield.

Automatic Operation

The user can select to operate the Blower, Recirculation and Air Delivery operations in auto per auto operation mode.

To put the HVAC system in full automatic mode, the following is required

  1. The auto button must be pressed.
  2. The system indicates that all 3 functions are being operated automatically by lighting the auto button LED.

When the auto button is pressed, the system responds by putting the blower, air delivery and recirculation into auto mode. If any of these functions are adjusted then the auto button indication shall go off and the function will leave auto operation and follow the user requested setting: auto, blower, air delivery and recirculation. In this setting the blower request is adjusted to quickly heat the cabin initially. After comfort is reached, the blower is mimized to reduce noise and temperature drifts.

Under cold ambient temperatures, the automatic HVAC system provides heat in the most efficient manner. The operator can select an extreme temperature setting but the system will not warm the vehicle any faster. Under warm ambient temperatures, the automatic HVAC system also provides air conditioning in the most efficient manner. Selecting an extreme cool temperature will not cool the vehicle any faster.

In automatic mode the values of the windshield temperature and inside moisture sensor are used as control inputs for the HVAC control module application to calculate the fog risk on the passenger compartment side of the windshield and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The A/C compressor and the defrost mode may be activated to prevent or remove fog on the passenger compartment side of the windshield. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield.

Coolant Heater Control Module

The coolant heater control module is an essential element of the hybrid heating system. The hybrid/EV powertrain control module 2 controls the passenger compartment heater coolant control valve , and the HVAC commands the coolant heater control module activation. Heated coolant either from the engine or the coolant heater control module will meet HVAC temperature demands. The coolant heater control module will be commanded "off" if the coolant temperature exceeds the desired temperature.

Coolant heat generated by the engine is also an element of the heating system. Once the engine coolant is warm enough to supply the required heat, the passenger compartment heater coolant control valve will move to the 'link' position, which allows sharing of coolant between the engine, the coolant heater control module and passenger compartment heater core. The coolant heater control module power level will be reduced and/or cycled on/off as the engine turns on/off during charge-sustaining mode, maintaining cabin comfort. When the engine is utilized for charge sustaining mode the thermostat will control the normal engine operating coolant temperature. The thermostat also creates a restriction for the cooling system that promotes a positive coolant flow and helps prevent cavitation.

Heater coolant enters the heater core through the inlet heater hose, in a pressurized state. The heater core is located inside the HVAC module. The ambient air drawn through the HVAC module, absorbs the heat of the coolant flowing through the heater core. Heated air is distributed to the passenger compartment, through the HVAC module, for passenger comfort. Opening or closing the air temperature flap controls the amount of heat delivered to the passenger compartment. The coolant exits the heater core through the return heater hose and recirculates back to the system as controlled by the coolant passenger compartment heater coolant control valve.

A/C Compressor Cycle

Refrigerant is the key element in an air conditioning system. R-134a is presently the only Environmental Protection Agency approved refrigerant for automotive use. R-134a is a very low temperature gas that can transfer the undesirable heat and moisture from the passenger compartment to the outside air.

The compressor builds pressure on the vapor refrigerant. Compressing the refrigerant also adds heat to the refrigerant. The refrigerant is discharged from the compressor, through the discharge hose, and forced to flow to the condenser and then through the balance of the A/C system.

Compressed refrigerant enters the condenser in a high temperature, high pressure vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid state.

The condenser is located in front of the radiator for maximum heat transfer. The condenser is made of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. The semi-cooled liquid refrigerant exits the condenser and flows to the Receiver/Dehydrator(R/D).

The R/D contains desiccant that absorbs moisture that may be in the refrigerant system. The R/D also acts as a storage vessel to ensure that a steady flow of liquid reaches the Thermal Expansion Valve (TXV). The refrigerant exits the R/D and flows through the liquid line to the TXV.

The TXV is located at the front of dash and attaches to the evaporator inlet and outlet pipes. The TXV is the dividing point for the high and the low pressure sides of the A/C system. As the refrigerant passes through the TXV, the pressure on the refrigerant is lowered. The TXV also meters the amount of liquid refrigerant that can flow into the evaporator.

Refrigerant exiting the TXV flows into the evaporator core in a low pressure, liquid state. The HVAC control module blows air through the evaporator core. Warm and moist air will cause the liquid refrigerant to boil inside of the evaporator core. The boiling refrigerant absorbs heat from the ambient air and draws moisture onto the evaporator. The refrigerant exits the evaporator through the suction line and back to the A/C compressor, in a vapor state, and completing the A/C cycle of heat removal. At the A/C compressor, the refrigerant is compressed again and the cycle of heat removal is repeated.

The conditioned air is distributed through the HVAC control module for passenger comfort. The heat and moisture removed from the passenger compartment will also change form, or condense, and is discharged from the HVAC control module as water through a drain to outside(underside) of the vehicle.

The A/C system is mechanically protected with the use of a high pressure relief valve. If the A/C refrigerant pressure sensor fails or if the refrigerant system becomes restricted and refrigerant pressure continued to rise, the high pressure relief will pop open and release refrigerant from the system.

See also:
• Blower Motor Control Module Replacement
• Radio Control Assembly Replacement
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• COMPONENT CONNECTOR END VIEWS - INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Temperature Versus Resistance
• Driver Information System Schematics
• Diagnostic Trouble Code (DTC) List - Vehicle
• DTC P0C43-P0C45
• Air Conditioning (A/C) System Performance Test
• Hybrid/EV Battery Pack Coolant Control Valve Learn
• High Voltage Disabling
• Special Tools
• DTC U0100-U02FF
• DTC U184B
• Checking Aftermarket Accessories
• Heating Performance Diagnostic
• HVAC System Control Module Programming and Setup
• Instrument Panel Compartment Replacement
• Fastener Caution
• Brake Pedal Assembly Replacement
• Instrument Panel Airbag Replacement
• Inside Rearview Mirror Wiring Harness Lower Cover Replacement
• Air Inlet Valve Actuator Replacement
• Temperature Valve Actuator Replacement - Left Side
• HVAC Component Replacement Reference
• Sensor Resistance Table
• Actuator Recalibration

More articles — HVAC