• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Outside Air Temperature Sensor | B0158 06 | B0158 05, B0158 06 | B0158 05 | -- |
Low Reference | -- | B0158 05, B0158 06 | -- | -- |
The body control module (BCM) monitors the outside air temperature sensor to display outside 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 outside air temperature sensor. The BCM provides the ground to the outside air temperature sensor through the low reference circuit. When the outside air temperatures are cold, the resistance of the sensor is high and the voltage signals are high. When the outside air temperatures are hot; the resistance of the sensor is low and the voltage signal is low. The BCM converts the voltage value to a temperature value of Celsius and Fahrenheit that will be displayed by the instrument panel cluster (IPC).
Ignition ON.
• | The BCM detects the sensor signal circuit is less than 0.1 volt. |
• | The BCM detects the sensor signal circuit is more than 4.9 volts. |
• | The default value of 3°C (38°F) will be substituted for the outside air temperature sensor data by the BCM. |
• | The IPC will display the set temperature when ON. |
• | The DTC will become history if the BCM no longer detects a failure. |
• | The history DTC will clear after 40 fault-free ignition cycles. |
Control Module References for scan tool information
Ignition ON, observe the scan tool Ambient Air Temp. Sensor parameter, the reading should be between 0.1 and 4.9 volts and change with temperature.
⇒ | 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 for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
⇒ | If not within the specified range, replace the sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |