HVAC System - Automatic Cadillac ATS I

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/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

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Ignition ON.
Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is less than -37°C (-35°F). If -37°C (-35°F) or greater Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. Test for infinite resistance between the signal circuit terminal 3 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC Control Module. If less than -37°C (-35°F)
Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.
Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is greater than 113°C (235°F). If 113°C (235°F) or less Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If greater than 113°C (235°F)
Test or replace the B10B Ambient Light/Sunload Sensor.
Verify DTC B0163 does not set or the symptom does not occur while operating the vehicle within the Conditions for Running the DTC. If the DTC or symptom is not corrected. Replace the K33 HVAC Control Module. If the DTC or symptom is corrected.
All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Upper Left Duct Air Temperature Sensor Signal	B0173 02	B0173 05	B0173 05
Lower Left Duct Air Temperature Sensor Signal	B0178 02	B0178 05	B0178 05
Upper Right Duct Air Temperature Sensor Signal	B0509 02	B0509 05	B0509 05
Lower Right Duct Air Temperature Sensor Signal	B0514 02	B0514 05	B0514 05
Air Conditioning Evaporator Temperature Sensor Signal	B3933 02	B3933 05	B3933 05
Low Reference		B0173 05, B0178 05, B0509 05, B0514 05, B3933 05	B0173 05, B0178 05, B0509 05, B0514 05, B3933 05

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

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

This sensor operates using signal and low reference circuits. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor is capable of reading temperatures ranging from -40 to +115°C (-40 to +240°F), with a signal voltage between 0-5 V. If the HVAC control module detects a malfunctioning sensor the software uses a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

Ignition ON.
The HVAC control module is ON.

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

The system operates using a default value.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/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

Ignition ON.
Verify the appropriate temperature sensor has a parameter displayed in HVAC scan tool information. If there is no scan tool parameter Refer to Circuit/System Testing - Without Scan Tool Support. If there is a scan tool parameter
Refer to Circuit/System Testing - With Scan Tool Support

With Scan Tool Support

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal B and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Ignition ON.
Verify the appropriate scan tool temperature sensor parameter is less than -37°C (-35°F) If greater than -37°C (-35°F) Ignition 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
Install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B.
Verify the scan tool temperature sensor parameter is greater than 110°C (230°F). If less than 110°C (230°F) Ignition OFF, remove the jumper wire and disconnect the harness connector at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If 110°C (230°F) or greater
Test or replace the temperature sensor.

Without Scan Tool Support

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal B and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Test for 4.8-5.2 V between the signal circuit terminal A and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for infinite resistance between the 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 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 Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC Control Module. If between 4.8-5.2 V
Test or replace the temperature sensor.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set. If the DTC sets Replace the K33 HVAC Control Module. If the DTC does not set
All OK

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

For symptom byte information, refer to Symptom Byte List .

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
5 V Reference	B1395 03	1	B1395 07
Signal Terminal 2	B048C 02	B048C 05	B048C 05
Signal Terminal 4	B018A 02	B018A 05	B018A 05
Signal Terminal 5	B048F 02	B048F 05	B048F 05
Low Reference		B018A 05, B048C 05, B048F 05, B1395 03
1. Sensor Malfunction

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

This sensor assembly provides information about

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

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

Ignition ON.
The HVAC control module is ON.

B018A 02, B048C 02, or B048F 02

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

B018A 05, B048C 05, B048F 05 or B1395 07

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

B1395 03

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

B1395 07

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

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

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B160 Windshield Temperature and Inside Moisture Sensor. It may take up to 10 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal 3 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Ignition ON.
Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If greater than 5.2 V Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC Control Module. If between 4.8-5.2 V
Verify the scan tool parameters listed below are less than -37°C (-35°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If -37°C (-35°F) or greater Ignition OFF, disconnect the harness connectors 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)
Install a 3 A fused jumper wire between the low reference circuit terminal 3 and each signal circuit terminal listed below: Windshield temperature sensor signal terminal 4 Passenger compartment humidity sensor temperature signal terminal 5
Verify the appropriate scan tool parameter listed below is greater than 114°C (238°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If 114°C (238°F) or less Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. 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)
Remove the jumper wire.
Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%. If 95% or less Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. 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%
Install a 3 A fused jumper wire between the passenger compartment humidity signal circuit terminal 2 and the low reference circuit terminal 3.
Verify the scan tool Passenger Compartment Humidity Sensor parameter is less than 5%. If 5% or greater Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V 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%
Test or replace the B160 Windshield Temperature and Inside Moisture Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

For symptom byte information, refer to Symptom Byte List .

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Signal	B0183 02	B0183 05	B0183 05
Low Reference		B0163 05, B0183 05

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

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

Ignition ON.
The HVAC Control Module is ON.

B0183 02

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

B0183 05

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

The system will use the last valid values as default.

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Ignition ON.
Test for 4.8-5.2 V between the signal circuit terminal 4 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module. 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 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 Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC Control Module. If between 4.8-5.2 V
Test or replace the B10B Ambient Light/Sunload Sensor.
Verify DTC B0183 does not set or the symptom does not occur while operating the vehicle within the Conditions for Running the DTC. If the DTC or symptom is not corrected. Replace the K33 HVAC Control Module. If the DTC or symptom is corrected.
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
B+	1	1
Control	B0193 06	B0193 06	B0193 01
Ground		1
1. HVAC Malfunction

The blower motor speed control signal from the HVAC control module, battery positive and ground circuits enable the blower motor to operate. The blower motor control circuitry is integrated within the blower motor assembly. The HVAC control module provides a ground pulse width modulation (PWM) signal to the blower motor to request a specific motor speed. The blower motor translates the PWM signal and drives the motor accordingly.

Ignition ON.
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 fluctuating.

The blower motor is inoperative.

The condition for setting the DTC is no longer present.

Diagnostic Aids

The current design of this motor does not allow for bench testing. The motor will not operate by simply applying power and ground.

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

Check for Preliminary Information or Technical Service Bulletins.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M8 Blower Motor. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the ground circuit terminal 1 and ground. If 10 ohms or greater 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
Ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition 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 Ignition 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 M8 Blower Motor. If the test lamp illuminates
Connect a test lamp between the control circuit terminal 2 and B+.
Verify the test lamp illuminates and there is a noticeable change when moving between commanded fan speeds. If there is not a noticeable change when moving between commanded fan speeds Ignition OFF, remove the test lamp and disconnect the X2 harness connector at the K33 HVAC Control Module ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V 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 there is a noticeable change when moving between commanded fan speeds
Replace the M8 Blower Motor.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5V Reference	B1395 03	B1395 07	B1395 07
Recirculation Actuator Signal	B0228 02	B0228 05	B0228 05	1
Main Temperature Actuator Signal	B0413 02	B0413 05	B0413 05	2
Right Temperature Actuator Signal	B0423 02	B0423 05	B0423 05	3
Mode Actuator Signal	B374A 02	B374A 05	B374A 05	4
Recirculation Actuator Control 1	1	1	1	1
Recirculation Actuator Control 2	1	1	1	1
Main Temperature Actuator Control 1	2	2	2	2
Main Temperature Actuator Control 2	2	2	2	2
Right Temperature Actuator Control 1	3	3	3	3
Right Temperature Actuator Control 2	3	3	3	3
Mode Actuator Control 1	4	4	4	4
Mode Actuator Control 2	4	4	4	4
Low Reference		B0228 05	B0228 05
Air Recirculation Malfunction Main Temperature Malfunction Right Temperature Malfunction Air Distribution Malfunction

The actuators are 5-wire bi-directional electric motors that incorporate a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a ground or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometer's sliding contact changes the door position signal between 0-5 V. When the module sets a commanded, or targeted, value, one of the control circuits is grounded, and the other is supplied 12 V. As the actuator shaft rotates, the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Ignition ON.
The HVAC control module is ON.

B0228 02, B0413 02, B0423 02 or B374A 02

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

B0228 05, B0413 05, B0423 05 or B374A 05

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

B1395 03

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

B1395 07

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

B1395

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

B0228, B0413, B0423 or B374A

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

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Perform the «Actuator Recalibration»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) procedure.
Verify the concern or DTC has been corrected. If the concern or DTC has not been corrected Verify DTC B1395 is not set. If DTC B1395 is set Refer to Circuit/System Testing - DTC B1395. If DTC B1395 is not set Refer to Circuit/System Testing - DTC B0228, B0413, B0423 or B374A.

DTC B1395

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down. M37 Mode Door Actuator M46 Air Recirculation Door Actuator M6L Air Temperature Door Actuator - Left M6R Air Temperature Door Actuator - Right
Disconnect the X3 and X4 harness connectors at the K33 HVAC Control Module.
Test for infinite resistance between the K33 HVAC Control Module 5 V reference circuit terminal 10 and ground. If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
Ignition ON.
Test for less than 1 V between the K33 HVAC Control Module 5 V reference terminal 10 and ground. If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
Clear all DTCs.
Ignition OFF, connect the X3 and X4 harness connectors at the K33 HVAC Control Module, ignition ON.
Verify DTC B1395 is not set. If the DTC is set. Replace the K33 HVAC Control Module. If the DTC is not set.
Verify DTC B1395 does not set after connecting each of the components listed below one at a time and operating them through their full range. M37 Mode Door Actuator M46 Air Recirculation Door Actuator M6L Air Temperature Door Actuator - Left M6R Air Temperature Door Actuator - Right If the DTC sets after connecting one of the components Replace the component that was connected immediately before the DTC set. If the DTC does not set
All OK.

DTC B0228, B0413, B0423 or B374A

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate door actuator. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal 2 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If less than 10 ohms
Ignition ON.
Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC Control Module. If between 4.8-5.2 V
Test for 4.8-5.2 V between the signal circuit terminal 3 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for infinite resistance between the 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 K33 HVAC Control Module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the 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 K33 HVAC Control Module. If between 4.8-5.2 V
Connect a test lamp between control circuit terminal 4 and control circuit terminal 5, ignition ON.
Verify the test lamp turns ON and then OFF when commanding the appropriate door actuator in both directions with a scan tool. If the test lamp does not turn ON and then OFF during either of the commands Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between each control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for infinite resistance between each control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for infinite resistance between the control circuits. If less than infinite resistance, repair the short on the circuit. If infinite resistance Test for less than 2 ohms in each 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 turns ON and then OFF during each of the commands
Test or replace the actuator.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Signal	B1405 02	B1405 05	B1405 05

The Ambient Light/Sunload Sensor integrates the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

Sun heat intensity
Passenger Compartment Temperature

The solar sensor is connected to ground and to the 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 coefficient 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.

This is a bidirectional sensor using a feedback circuit for the HVAC module to send information to the sensor. It is a fault on this feedback circuit that causes this DTC to set.

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.

Ignition ON
The HVAC Control Module is ON.

B1405 02

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

B1405 05

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

The system will use the last valid values as default.

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 2 min for all vehicle systems to power down.
Test for greater than 10 V between signal circuit terminal 2 and ground. If less than 10 V Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module. Test for infinite resistance between signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If 10 V or greater
Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit terminal 20 and ground. If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
Test or replace the B10B Ambient Light/Sunload Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

DTC Descriptor

For symptom byte information, refer to Symptom Byte List .

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
B+	1	B393B 04
Control	B393B 04	B393B 04	B393B 0B
1. Solenoid Valve Malfunction

This A/C system uses a conventional clutch to engage and mechanically turn the compressor and a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. The HVAC control module provides both battery voltage and a pulse width modulated ground to the variable displacement solenoid valve. When the A/C switch is pressed, the HVAC control module grounds the variable displacement solenoid using a low side (PWM) signal in order to command the amount of compressor displacement. The performance of the A/C compressor is based on adjusted interior temperature and engine load.

Ignition ON.
The HVAC control module is ON.

B393B 04

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

B393B 0B

Measured current is above threshold of 815 mA.

B393B 04

The A/C compressor is disabled.

B393B 0B

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

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF, disconnect the harness connector at the Q46 A/C Compressor Solenoid Valve, ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate Ignition OFF, remove the test lamp and disconnect the harness connectors at the K33 HVAC Control Module. Test for infinite resistance between the Q46 A/C Compressor Solenoid Valve B+ 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 B+ 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 illuminates
Ignition OFF, connect a test lamp between the control circuit terminal 1 and the B+ circuit terminal 2, ignition ON.
Verify the test lamp turns ON and OFF when commanding the Q46 A/C Compressor Refrigerant Solenoid Valve On and Off with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON. Test for less than 1 V between the Q46 A/C Compressor Refrigerant Solenoid Valve control circuit terminal 1 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC Control Module. If the test lamp is always ON Ignition OFF, remove the test lamp and disconnect the harness connectors at the K33 HVAC Control Module. Test for infinite resistance between the Q46 A/C Compressor Refrigerant Solenoid Valve control 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 the test lamp turns ON and OFF
Test or replace the G1 A/C Compressor.

Component Testing

A/C Compressor Solenoid Valve Test

Ignition OFF, disconnect the harness connector at the Q46 A/C Compressor Solenoid Valve.
Test for 7-15 ohms between B+ terminal 2 and control terminal 1. If less than 7 ohms or greater than 15 ohms Replace the G1 A/C Compressor. If between 7-15 ohms
Test for infinite resistance between each terminal and the Q46 A/C Compressor Solenoid Valve housing/case. If less than infinite resistance Replace the G1 A/C Compressor. If infinite resistance
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of the diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
5 V Reference	P0532, P0641	P0532	P0533
Signal	P0532	P0532	P0533
Low Reference		P0533

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

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

P0532

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

P0533

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

DTCs P0532 and P0533 are Type B DTCs
The A/C compressor is disabled.
The ECM will illuminate the malfunction indicator lamp (MIL).

The condition for setting the DTC is no longer present.

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

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/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

Ignition ON
Verify the scan tool engine control module A/C High Side Pressure Sensor parameter is between 6.8 kPa (1 psi) and 2950 kPa (428 psi). If not between 6.8 kPa (1 psi) and 2950 kPa (428 psi) Refer to Circuit/System Testing If between 6.8 kPa (1 psi) and 2950 kPa (428 psi)
All OK

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B1 A/C Refrigerant Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the low reference circuit terminal 1 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K20 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 10 ohms
Ignition ON.
Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K20 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 Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If between 4.8-5.2 V
Verify the scan tool A/C High Side Pressure Sensor parameter is less than .25 V. If .25 V or greater Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If less than .25 V
Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.
Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.8 V. If 4.8 V or less Ignition OFF, remove the jumper wire, 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 4.8 V
Test or replace the B1 A/C Refrigerant Pressure Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Relay Coil Ignition	P0645	P0645
Relay Switch B+	1	1
Relay Coil Control	P0646	P0645	P0647
Relay Switch Control	1	1	1
Ground		1
1. A/C Compressor Malfunction

When the A/C switch is pressed, the HVAC control module sends an A/C request message to the engine control module (ECM) via serial data. The ECM then grounds the A/C compressor clutch relay coil control circuit, closing the relay contacts. The closed relay contacts provide voltage to the compressor clutch causing it to engage.

Engine is running.
The HVAC control module is ON.
The A/C switch is active.

P0645 or P0646

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

P0647

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

P0645 or P0646

The A/C compressor is inoperative or always active. The A/C compressor solenoid is commanded to 0% displacement. This causes warm air from the ducts, even with unwanted clutch engagement.

P0647

The A/C compressor is inoperative.

The condition for setting the DTC is no longer present.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/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

Ignition OFF, disconnect the KR29 A/C Compressor Clutch Relay, ignition ON.
Verify a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition 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 Ignition 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, Disconnect the harness connector at the Q2 A/C Compressor Clutch. Test for infinite resistance between the control circuit terminal 5 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, test or replace the Q2 A/C Compressor Clutch. If the test lamp illuminates
Ignition ON.
Verify a test lamp illuminates between the ignition circuit terminal 1 and ground. If the test lamp does not illuminate Refer to «Power Mode Mismatch»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) . If the test lamp illuminates
Connect a test lamp between the ignition circuit terminal 1 and the control circuit terminal 2.
Verify the test lamp turns ON and OFF when commanding the Engine Control Module A/C Compressor Clutch Relay On and Off with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp. Disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If the test lamp is always ON Ignition OFF, remove the test lamp. Disconnect the harness connector at the K20 Engine Control Module, Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If the test lamp turns ON and OFF
Verify a test lamp does not illuminate between the control circuit terminal 5 and ground. If the test lamp illuminates Repair the short to voltage on the circuit. If the test lamp does not illuminate
Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q2 A/C Compressor Clutch. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 ohms between the ground circuit terminal 1 and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
Connect the harness connector at the Q2 A/C Compressor Clutch.
Ignition ON, connect a 10 A fused jumper wire between the B+ circuit terminal 3 and the control circuit terminal 5.
Verify the Q2 A/C Compressor Clutch is activated. If the Q2 A/C Compressor Clutch does not activate Ignition OFF, disconnect the harness connector at the Q2 A/C Compressor Clutch. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the Q2 A/C Compressor Clutch. If the Q2 A/C Compressor Clutch activates
Test or replace the KR29 A/C Compressor Clutch Relay.

Ignition OFF, disconnect the KR29 A/C Compressor Clutch Relay.
Test for 60-180 ohms between terminals 85 and 86. If not between 60-180 ohms Replace the KR29 A/C Compressor Clutch Relay. If between 60-180 ohms
Test for infinite resistance between the terminals listed below: 30 and 86 30 and 87 30 and 85 85 and 87 If less than infinite resistance Replace the KR29 A/C Compressor Clutch Relay. If infinite resistance
Install a 15 A fused jumper wire between terminal 86 and 12 V. Install a jumper wire between terminal 85 and ground.
Test for less than 2 ohms between terminals 30 and 87. If 2 ohms or greater Replace the KR29 A/C Compressor Clutch Relay. If less than 2 ohms
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

«Relay Replacement (Within an Electrical Center)»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/cadillac/ats/i-2012-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming and setup

Symptoms - HVAC Systems - Automatic

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

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the HVAC System Malfunction procedure in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
Review the system operation in order to familiarize yourself with the system functions. Refer to «Automatic HVAC Description and Operation»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__automatic-hvac-description-and-operation) .

Visual/Physical Inspection

Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
Verify the A/C compressor turns freely and is not seized.
Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
The A/C compressor will not operate in cold outside air temperatures.
The following conditions may cause window fogging: Wet carpet or mats High humidity Interior water leak Blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
Inspect the air distribution system for causes of reduced air flow: Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

Intermittent

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

Symptom List

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

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Check the following mechanical fault sources

Air distribution box
Air distribution hoses/air distribution ducts

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

R-134a - J43600 ACR Air Conditioning Service Center
R-1234yf - GE-50300 ACR Air Conditioning Service Center

Note. Check for bulletins before proceeding.

Ignition ON.
Verify every applicable scan tool Switch parameter changes when pressing the appropriate switch on the A20 Radio/ HVAC Controls. If any parameter does not change Replace the A20 Radio/ HVAC Controls. If all parameters change
Verify the blower motor operates properly with the blower motor switch in each speed position. If the blower motor does not operate in each speed position Refer to «DTC B0193»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If the blower motor operates properly in each speed position
Verify the HVAC doors listed below move when pressing the appropriate switch. Driver Temperature Passenger Temperature Mode Recirculation If any HVAC door does not move Refer to «DTC B0228, B0413, B0423, B1395, or B374A»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If all HVAC doors move
Install the appropriate ACR Air Conditioning Recharge Service Center.
Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool A/C High Side Pressure Sensor parameter. If the reading is not within 10% Refer to «DTC P0532 or P0533»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If the reading is within 10%
Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI). If the reading is not between 269-2929 kPa (39-425 PSI) Refer to «Air Conditioning (A/C) System Performance Test (LFX, LTG)»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) , «Air Conditioning (A/C) System Performance Test (LCV)»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) If the reading is between 269-2929 kPa (39-425 PSI)
Verify the scan tool parameters listed below are within 10% of ambient temperature. Lower Left Duct Air Temperature Sensor Upper Left Duct Air Temperature Sensor Lower Right Duct Air Temperature Sensor Upper Right Duct Air Temperature Sensor A/C Evaporator Temperature Sensor If not within 10% of ambient temperature Refer to «DTC B0173, B0178, B0509, B0514 or B3933»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If within 10% of ambient temperature
Verify the scan tool parameters listed below are within 10% of actual conditions. Passenger Compartment Humidity Passenger Compartment Humidity Sensor Temperature Passenger Compartment Windshield Temperature If not within 10% of actual conditions Refer to «DTC B018A, B048C, B048F, or B1395»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If within 10% of actual conditions
Engine ON, A/C system ON
Verify cool air flows from the ducts with the temperature control in the coldest position. If the air is not cool Verify the Q2 A/C Compressor Clutch is engaged. If the Q2 A/C Compressor Clutch is not engaged, refer to «Air Conditioning Compressor Malfunction»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If the Q2 A/C Compressor Clutch is engaged, refer to «Air Conditioning (A/C) System Performance Test (LFX, LTG)»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) , «Air Conditioning (A/C) System Performance Test (LCV)»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__air-conditioning-ac-system-performance-test) , and «DTC B393B»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If the air is cool
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/ats/i-2012-2014/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning__heating-performance-diagnostic) . If the air is warm
Engine OFF, ignition ON.
Verify the 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 B0163»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If the Sunload parameter changes
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 Temp. Sensor parameter. If greater than a 3°C (5°F) difference Refer to «DTC B0183»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic) . If less than a 3°C (5°F) difference
All OK.

Perform the Diagnostic Repair Verification after completing the repair.

«HVAC Component Replacement Reference»(/cadillac/ats/i-2012-2014/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
«Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
A/C Compressor Clutch Relay Switch B+	1	1
A/C Compressor Clutch Relay Coil Ignition	P0645	P0645, P0646
A/C Compressor Clutch Relay Coil Control	P0645	P0645, P0646	P0647
A/C Compressor Valve Control (+)	B393B 04	B393B 04
A/C Compressor Valve Control (-)	B393B 04	B393B 04	B393B 0B	1
A/C Compressor Clutch Control	1	1	2
A/C Compressor Clutch Ground		1
1. A/C Compressor Inoperative 2. A/C Compressor Always ON

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

This A/C system utilizes a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. The HVAC control module provides both battery voltage and a pulse width modulated ground to the variable displacement solenoid valve. When the A/C switch is pressed, the HVAC control module grounds the variable displacement solenoid using a (PWM) signal in order to determine the amount of compressor displacement. The performance of the A/C compressor is regulated based on the adjusted interior temperature.

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

Battery voltage is between 9-18 V.
Engine coolant temperature is less than 124°C (255°F).
Engine speed is greater than 600 RPM.
Engine speed is less than 5500 RPM.
A/C high side pressure is between 269-2 929 kPa (39-425 PSI).
Throttle position is less than 100%.
Evaporator temperature is greater than 3°C (38°F).
ECM does not detect excessive torque load.
ECM does not detect insufficient idle quality.
The ambient temperature is above 1°C (34°F).

Schematic Reference

Connector End View Reference

Description and Operation