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 Short to GroundDTC B0158 05: Outside Air Temperature Sensor 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 | 1 |
Upper Air Temperature Sensor Signal | B0173 06 | B0173 05 | B0173 05 | 1 |
Lower Air Temperature Sensor Signal | B0178 06 | B0178 05 | B0178 05 | 1 |
Sunload Sensor Signal | B0183 02 | B0183 05 | B0183 05 | 1 |
Ambient Air Temperature Sensor Low Reference | -- | B0158 05 | -- | -- |
Upper Air Temperature Sensor Low Reference | -- | B0173 05 | -- | -- |
Lower Air Temperature Sensor Low Reference | -- | B0178 05 | -- | -- |
Sunload Sensor Low Reference | -- | B0183 05 | -- | -- |
Sunload Sensor Ground | -- | B0183 05 | -- | -- |
1. Air Temperature Malfunction | ||||
Circuit/System Description
The body control module (BCM) monitors the ambient air temperature sensor to display ambient air temperature. The temperature sensor is a 2-wire negative temperature co-efficient thermistor. The BCM applies 5 volts to an internal input resistor that is connected to the signal circuits of the ambient air temperature sensor. The BCM provides the ground to the ambient air temperature sensor through the low reference circuit. The BCM 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 BCM 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
Ignition ON.
Conditions for Setting the DTC
| • | The BCM detects the sensor signal circuit is less than 0.05 volt. |
| • | The BCM detects the sensor signal circuit is greater than 4.9 volts. |
Action Taken When the DTC Sets
| • | The default value of 85°C (185°F) will be substituted for the ambient air temperature sensor data by the HVAC control module. |
| • | The DIC will display actual temperature. |
Conditions for Clearing the DTC
| • | The DTC will become history if the BCM 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 scan tool HVAC Control Module Ambient Air Temp Sensor parameter. The reading should be between -35 and +85°C (-39 and +185°F) and change with air temperature changes.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the ambient air temperature sensor.
- Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal B and ground.
- Ignition ON, verify the scan tool BCM Ambient Air Temp Sensor parameter is greater than 4.8 volts.
- Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool BCM Air Temp Sensor parameter is less than 0.20 volt.
- If all circuits test normal, test or replace the ambient air temperature sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
