B0158
DTC B0158
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
DTC B0158 02
- Outside Air Temperature Sensor Circuit Short to Ground
DTC B0158 05
- Outside Air Temperature Sensor Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit/System Description
The HVAC control module monitors the ambient air temperature sensor to display ambient air temperature. The temperature sensor is a 2-wire negative temperature co-efficient thermistor. The HVAC control module volts to an internal input resistor that is connected to the signal circuits of the ambient air temperature sensor. The HVAC control module provides the ground to the ambient air temperature sensor through the low reference circuit. The HVAC control module monitors the voltage drop across the ambient air temperature sensor and uses the input for automatic control calculations. When the ambient air temperatures are cold, the resistance of the sensor is high and the voltage signals are high. When the ambient air temperatures are hot, the resistance of the sensors is low and the voltage signals are low. The HVAC control module converts the voltage value to a temperature value of Celsius and Fahrenheit that will be displayed by the driver information center (DIC).
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
* The HVAC control module detects the sensor signal circuit is less than 0.1 volt or 5 counts.
* The HVAC control module detects the sensor signal circuit is more than 4.9 volts or 250 counts.
Action Taken When the DTC Sets
The HVAC control module uses a default air temperature value for further automatic control calculations. The default values are not displayed on the scan tool.
Conditions for Clearing the DTC
* The DTC will become history if the HVAC control module no longer detects a failure.
* The history DTC will clear after 100 fault-free ignition cycles.
* The DTC can be cleared with a scan tool.
Circuit/System Testing
1. Ignition OFF, disconnect the ambient air temp sensor harness connector at the ambient air temp sensor.
2. Test for less than 1.0 ohm of resistance between the low reference circuit terminal 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 Ambient Air Temp Sensor voltage parameter is greater than 4.9 volts or 250 counts.
• If less than 0.1 volt or 5 counts 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 Ambient Air 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, replace the Ambient Air Temp Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Ambient Air Temperature Sensor Replacement
* Programming and RelearningProgramming and Relearning