B0514
DTC B0158, B0163, B0173, B0178, B0509, or B0514
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
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 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/System Description
Air Temperature Sensors
The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors:
* Ambient Air Temperature Sensor
* Inside Air Temperature Sensor Assembly
* Upper Left Air Temperature Sensor
* Upper Right Air Temperature Sensor
* Lower Left Air Temperature Sensor
* Lower Right Air Temperature Sensor
A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +101°C (-40 to +215°F). The sensor signal varies between 0-5 volts. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease. If the HVAC control module or auxiliary HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted air temperature value. The default value for the ambient and inside air temperature sensors will be displayed on the scan tool. The default value for the duct air temperature sensors will not be displayed on the scan tool. The scan tool parameter for the duct air temperature sensors are the actual state of the signal circuit. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.
Diagnostic Aids
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
The HVAC control module detects the temperature sensor signal circuit is less than -35°C (-39°F) or greater than 85°C (185°F) for greater than 15 seconds.
Action Taken When the DTC Sets
The system operates using a default value.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 100 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics (HVAC - Automatic)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Air Temperature Description and Operation (Air Temperature)
* Air Delivery Description and Operation (Air Delivery)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Measure actual outside air temperature using a thermometer. Compare this value to the scan tool Outside Air Temp. Raw parameter. The measured temperature should be within 5 degrees of parameter.
• If not within the specified range, refer to Ambient/Inside Air Temperature Sensor Circuit Malfunction.
2. Measure actual inside air temperature using a thermometer. Compare this value to the scan tool Inside Air Temp. Sensor parameter and Aux. Inside Air Temp. parameter. The measured temperature should be within 5 degrees of parameter.
• If not within the specified range, refer to Ambient/Inside Air Temperature Sensor Circuit Malfunction.
3. Measure actual temperature using a thermometer at each of the duct temperature sensors. Compare this value to the appropriate scan tool Duct Actual parameter. The measured temperature should be within 5 degrees of appropriate Duct Actual parameter.
• If not within the specified range, refer to Duct Temperature Sensor Circuit Malfunction.
Circuit/System Testing
Ambient/Inside Air Temperature Sensor Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for less than 1 ohm between the low reference circuit terminal B and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
3. Ignition ON, verify the appropriate scan tool Temp Sensor parameter is greater than 85°C (185°F).
• If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp Sensor parameter is less than less than -35°C (-39°F).
• 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.
Duct Temperature Sensor Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for less than 1.0 ohm between the low reference circuit terminal 2 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
3. Ignition ON, verify the appropriate Duct Temp Sensor Actual parameter is greater than 85°C (185°F).
• If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module.
4. Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Duct Temp Sensor Actual parameter is less than -35°C (-39°F)
• 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.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
2. Test for the appropriate resistance between the signal terminal A or 1 and the low reference terminal B or 2. Refer to Sensor Resistance Table (Electrical Specifications) for resistance values.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Duct Air Temperature Sensor Replacement - Lower Left Side (Duct Air Temperature Sensor Replacement - Lower Left Side)
* Duct Air Temperature Sensor Replacement - Lower Right Side (Duct Air Temperature Sensor Replacement - Lower Right Side)
* Ambient Air Temperature Sensor Replacement (Service and Repair)
* Inside Air Temperature Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup, and programming