B0173
DTC B0158, B0163, B0168, B0173, B0178, B0509, B0514, B3578 or B3583
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
The diagnostic procedure supports the following DTCs:
* DTC B0158 02 Outside Air Temperature Sensor Circuit Short to Ground
* DTC B0158 05 Outside Air Temperature Sensor Circuit Short to Battery or Open
* DTC B0163 02 Passenger Compartment Temp Sensor 1 Circuit Short to Ground
* DTC B0163 05 Passenger Compartment Temp Sensor 1 Circuit Short to Battery or Open
* DTC B0168 02 Passenger Compartment Temp Sensor 2 Circuit Short to Ground
* DTC B0168 05 Passenger Compartment Temp Sensor 2 Circuit Short to Battery or Open
* DTC B0173 02 Output Air Temperature Sensor 1 Circuit Short to Ground
* DTC B0173 05 Output Air Temperature Sensor 1 Circuit Short to Battery or Open
* DTC B0178 02 Output Air Temperature Sensor 2 Circuit Short to Ground
* DTC B0178 05 Output Air Temperature Sensor 2 Circuit Short to Battery or Open
* DTC B0509 02 Output Air Temperature Sensor 3 Circuit Short to Ground
* DTC B0509 05 Output Air Temperature Sensor 3 Circuit Short to Battery or Open
* DTC B0514 02 Output Air Temperature Sensor 4 Circuit Short to Ground
* DTC B0514 05 Output Air Temperature Sensor 4 Circuit Short to Battery or Open
* DTC B3578 02 Output Air Temperature Sensor 6 Circuit Short to Ground
* DTC B3578 05 Output Air Temperature Sensor 6 Circuit Short to Battery or Open
* DTC B3583 02 Output Air Temperature Sensor 7 Circuit Short to Ground
* DTC B3583 05 Output Air Temperature Sensor 7 Circuit Short to Battery or Open
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/C Evaporator Temperature Sensor
A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +101°C (-40 to +215°F). The sensor signal varies between 0-5 volts. The input of the duct air temperature sensors are different from the ambient and inside air temperature sensors. 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
The ignition is turned ON.
Conditions for Setting the DTC
The HVAC control module detects the inside air temperature sensor signal circuit is less than -36°C (-38°F) or greater than 215°C (419°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 50 fault-free ignition cycles.
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. 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 / Evaporator Temperature Sensor Circuit Malfunction.
4. Measure actual temperature using a thermometer at the A/C evap. temperature sensor. Compare this value to the scan tool A/C Evap. Temperature Sensor parameter. The measured temperature should be within 5 degrees of the parameter.
• If not within the specified range, refer to Duct Temperature / Evaporator 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 Voltage parameter is greater than 4.9 volts or 250 counts.
• 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 Voltage parameter is less than 0.1 volt or 5 counts.
• 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 / Evaporator 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 temp sensor parameter is greater than 4.9 volts or 250 counts.
• 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 temp sensor parameter is less than 0.1 volt or 5 counts.
• 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.
If not within the specified range, replace the appropriate sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Air Temperature Sensor Replacement - Upper Auxiliary (Behr)
* Air Temperature Sensor Replacement - Upper Right Side
* Air Temperature Sensor Replacement - Upper Left Side
* Air Temperature Sensor Replacement - Lower Auxiliary (Delphi)
* Air Temperature Sensor Replacement - Lower Left Side
* Air Temperature Sensor Replacement - Lower Right Side
* Ambient Air Temperature Sensor Replacement
* Inside Air Temperature Sensor Replacement
* Auxiliary Inside Air Temperature Sensor Assembly Replacement