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

Diagnostic Instructions

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

DTC Descriptors

DTC B0163

Passenger Compartment Temperature Sensor Circuit

DTC B0183

Solar Load Sensor Circuit

DTC B1405

Control Module Voltage Reference Output 2 Circuit

For symptom byte information, refer to Symptom Byte List .

Diagnostic Fault Information

Circuit/System Description

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

The solar sensor uses 4 unique circuits as detailed below:

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

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

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

Conditions for Running the DTC

• Ignition ON
• The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02

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

B0163 05

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

B0163 05

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

B0183 02

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

B0183 05

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

B1405 02

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

B1405 05

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

Action Taken When the DTC Sets

B0163 02, B0163 05, B0183 02, B0183 05

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

B1405 02, B1405 05

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

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

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

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

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

If both DTCs are set

Refer to Low Reference Test.

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

If one of the DTCs is set

Refer to the appropriate diagnostic in Circuit/System Testing.

If none of the DTCs are set

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

If the sensor is not accurate

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

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

If the sensor is accurate

4. All OK.

Circuit/System Testing

Low Reference Test

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

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

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

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

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

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

If less than 10 ohms

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

DTC B0163

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

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

If -37ºC (-35ºF) or greater

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

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

If less than -37ºC (-35ºF)

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

If 78ºC (172ºF) or less

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

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

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

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

If greater than 78ºC (172ºF)

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

DTC B0183

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

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

If less than 4.8 V

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

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

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

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

If greater than for 5.2 V

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

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

If between 4.8-5.2 V

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

If DTC B0183 reset

Replace the K33 HVAC Control Module.

If DTC B0183 did not reset

5. All OK.

DTC B1405

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

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

If less than 10 V

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

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

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

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

If 10 V or greater

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

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

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

If DTC B1405 reset

Replace the K33 HVAC Control Module.

If DTC B1405 did not reset

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

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

Diagnostic Instructions

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

DTC Descriptors

DTC B0173 02

Upper Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0173 05

Upper Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0178 02

Lower Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0178 05

Lower Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0509 02

Upper Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0509 05

Upper Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0514 02

Lower Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0514 05

Lower Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B3933 02

Air Conditioning Evaporator Temperature Sensor Circuit Short to Ground

DTC B3933 05

Air Conditioning Evaporator Temperature Sensor Circuit High Voltage/Open

Diagnostic Fault Information

Circuit/System Description

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

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

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

Conditions for Running the DTC

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

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

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

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

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

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

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

If DTC B3933 is set

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

If DTC B3933 is not set

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

If there is no scan tool parameter

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

If there is a scan tool parameter

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

Circuit/System Testing

With Scan Tool Support

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

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

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

If 10 ohms or greater

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

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

If less than 10 ohms

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

If greater than -37ºC (-35ºF)

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

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

If -37ºC (-35ºF) or less

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

If less than 77ºC (170ºF)

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

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

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

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

If 77ºC (170ºF) or greater

7. Test or replace the temperature sensor.

Without Scan Tool Support

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

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

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

If 10 ohms or greater

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

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

If less than 10 ohms

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

If less than 4.8 V

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

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

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

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

If greater than 5.2 V

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

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

If between 4.8-5.2 V

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

If the DTC sets

Replace the K33 HVAC Control Module.

If the DTC does not set

7. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair

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

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