Diagnostic Instructions

DTC Descriptors

DTC B0158 05: Outside Air Temperature Sensor Circuit Short to Battery or Open

DTC B0158 02: Outside Air Temperature Sensor Circuit Short to Ground

DTC B0163 05: Passenger Compartment Temp Sensor 1 Circuit Short to Battery or Open

DTC B0163 02: Passenger Compartment Temp Sensor 1 Circuit Short to Ground

DTC B0168 05: Passenger Compartment Temp Sensor 2 Circuit Short to Battery or Open

DTC B0168 02: Passenger Compartment Temp Sensor 2 Circuit Short to Ground

DTC B0173 05: Output Air Temperature Sensor 1 Circuit Short to Battery or Open

DTC B0173 02: Output Air Temperature Sensor 1 Circuit Short to Ground

DTC B0178 05: Output Air Temperature Sensor 2 Circuit Short to Battery or Open

DTC B0178 02: Output Air Temperature Sensor 2 Circuit Short to Ground

DTC B0509 05: Output Air Temperature Sensor 3 Circuit Short to Battery or Open

DTC B0509 02: Output Air Temperature Sensor 3 Circuit Short to Ground

DTC B0514 05: Output Air Temperature Sensor 4 Circuit Short to Battery or Open

DTC B0514 02: Output Air Temperature Sensor 4 Circuit Short to Ground

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Upper Left Air Temperature Sensor Signal	B0173 02	B0173 05	B0173 05	--
Upper Right Air Temperature Sensor Signal	B0509 02	B0509 05	B0509 05	--
Lower Left Air Temperature Sensor Signal	B0178 02	B0178 05	B0178 05	--
Lower Right Air Temperature Sensor Signal	B0514 02	B0514 05	B0514 05	--
Ground	--	B0173 05, B0509 05, B0178 05, B0514 05, B0158 05, B0163 05	B0173 05, B0509 05, B0178 05, B0514 05, B0158 05, B0163 05	--

Circuit/System Description

Air temperature sensors allow the HVAC control module to monitor the temperature of the discharge air in the HVAC ducts. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. When the duct air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the duct air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where one volt is approximately equal to 51 counts.

DTC B0158

This DTC is for the Outside Air Temperature Sensor

DTC B0163

This DTC is for the Passenger Compartment Air Temperature Sensor

DTC B0173

This DTC is for the Left Upper Air Temperature Sensor

DTC B0178

This DTC is for the Left Lower Air Temperature Sensor

DTC B0509

This DTC is for the Right Upper Air Temperature Sensor

DTC B0514

This DTC is for the Right Lower Air Temperature Sensor

Conditions for Running the DTC

The ignition is turned On.

Conditions for Setting the DTC

The HVAC control module detects the signal circuit is less than 0.09 volts (5 counts) or more than 4.90 volts (250 counts).

Action Taken When the DTC Sets

The Auto feature of the HVAC control module will be inoperative.

Conditions for Clearing the DTC

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

HVAC Connector End Views

Description and Operation

Air Temperature Description and Operation

Electrical Information Reference

Scan Tool Reference

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the appropriate ground circuit terminal and ground.

•	Duct temperature sensor ground circuit terminal A

•	Ambient temperature sensor ground circuit terminal B

•	Inside air temperature sensor ground circuit terminal C

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the appropriate scan tool temperature sensor parameter is greater than 250  counts.

⇒	If less than the specified range, test the appropriate signal circuit terminal for a short to ground. If the circuit tests normal, replace the HVAC control module.

•	Duct temperature sensor signal circuit terminal B

•	Ambient temperature sensor signal circuit terminal A

•	Inside air temperature sensor signal circuit terminal B

4. Install a 3A fused jumper wire between the appropriate signal circuit terminal and ground. Verify the appropriate scan tool temperature sensor parameter is less than 5 counts.

•	Duct temperature sensor signal circuit terminal B

•	Ambient temperature sensor signal circuit terminal A

•	Inside air temperature sensor signal circuit terminal B

⇒	If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

5. If all circuits test normal, test or replace the appropriate temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.