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 B0158 02: Outside Air Temperature Sensor Circuit Short to GroundDTC B0158 05: Outside Air Temperature Sensor Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ambient Air Temperature Sensor Signal | B0158 02 | B0158 05 | B0158 05 | -- |
Evaporator Temperature Sensor Signal | B3933 02 | B3933 05 | B3933 05 | -- |
Low Reference | -- | B3933 05, B0158 05 | B3933 05, B0158 05 | -- |
Circuit/System Description
The HVAC control module monitors the ambient air temperature sensor with a low reference circuit and 5-volt signal circuit. The HVAC control module monitors the voltage drop across the sensor, which is proportional to temperature. 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 -35°C (-39°F). |
| • | The HVAC control module detects the sensor signal circuit is more than 85°C (185°F) . |
Action Taken When the DTC Sets
The HVAC control module uses a default air temperature value for compressor clutch operation.
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. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit/System Verification
Ignition ON, observe the ambient air temperature sensor. The reading should be between -35°C (-39°F) and 85°C (185°F) and change with ambient air temperature changes.
Circuit/System Testing
Important: If the ambient air temperature sensor is in temperatures below 2°C (35°F) the compressor clutch will be disabled until the vehicle is driven above 45 mph (72 km/h), the ignition is OFF for more than 3 hours or an instant OAT update is performed.
Important: An instant OAT update must be performed by pressing the A/C and Recirc buttons at the same time before and after the system has been serviced to update the filtered ambient air temperature sensor circuit and convert the A/C permission from withheld to granted.
- Ignition OFF, disconnect the harness connector at the ambient air temp sensor.
- Ignition OFF, test for less than 10 ohms of resistance between the low reference circuit terminal B and ground.
- Ignition ON, verify the scan tool Ambient Air Temp Sensor parameter is less than -35°C (-39°F).
- Install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Ambient Air Temp Sensor Raw parameter is greater than 85°C (185°F).
- If all circuits test normal, test or replace the ambient air temp sensor.
| ⇒ | 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. |
| ⇒ | If greater 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. |
| ⇒ | If less 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. |
Important: An instant OAT update must be performed to grant A/C permission after testing or replacing the ambient air temperature sensor.
Component Testing
- Test the ambient air temperature sensor by varying the sensor temperature while monitoring the sensor resistance.
- Compare the readings with the Temperature VS Resistance table and verify that the resistance is within 5 percent of the specification.
Important: Sensor Resistance Table for this test. A thermometer can be used to test the sensor off the vehicle in warn and or cold water.
| ⇒ | If not within the specified range, replace the sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for HVAC control module replacement, setup, and programming |
