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 01: Outside Air Temperature (OAT) Sensor Short to Battery or OpenDTC B0158 02: Outside Air Temperature (OAT) Sensor Short to Ground
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage |
|---|---|---|---|---|
Ambient Air Temperature Signal | B0158 | 1 | B0158 | B0158 |
Ambient Air Temperature Low Reference | -- | 1 | B0158 | -- |
1. Outside Air Temperature Display Inaccurate or Inoperative | ||||
Circuit/System Description
The ambient air temperature sensor is a variable resistor interfaced to the underhood electrical center (UEC). The ambient air temperature sensor is a 2-wire negative temperature coefficient thermistor. The UEC applies voltage to an internal input resistor connected to the signal circuit of the ambient air temperature sensor. When the ambient air temperature is cold, the sensor resistance is high and the signal voltage is high. When the ambient air temperature is hot, the sensor resistance is low and the signal voltage is low. The UEC provides the logic for reading the sensor, filtering the data and transmitting the information via the serial data circuit to the driver information center (DIC) for display.
Conditions for Running the DTC
| • | The ignition is in ACC or RUN. |
| • | The system voltage is between 9-16 volts |
Conditions for Setting the DTC
| • | The UEC detects that the ambient air temperature sensor is -40°C (-40°F) or less. |
| • | The UEC detects that the ambient air temperature sensor is 87°C (188°F) or greater. |
Action Taken When the DTC Sets
| • | The last valid value is frozen and retained by the ambient air temperature sensor. |
| • | The driver information center (DIC) will display SET TEMPERATURE when ON. |
Conditions for Clearing the DTC
| • | The DTC becomes history when the UEC no longer detects a fault. |
| • | The history DTC clears after 40 malfunction-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 Testing
- Ignition OFF, disconnect the harness X1 harness connector at the ambient air temperature sensor.
- Ignition OFF, test for less than 1 ohm between the low reference circuit terminal 2 and ground.
- Ignition ON, verify the scan tool Ambient Air Temp. Sensor parameter is approximately -40°C (-40°F).
- Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool Ambient Air Temp. Sensor parameter is approximately 87°C (188°F).
- 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 ECM. |
| ⇒ | If greater than the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the UEC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for the UEC replacement, setup, and programming |
