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 13: Outside Air Temperature Sensor Voltage Low.DTC B0158 14: Outside Air Temperature Sensor Voltage High.
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ambient Air Temperature Sensor Signal Circuit | B0158 14 | B0158 14 B0158 13 | B0158 13 | -- |
Low Reference Circuit | -- | B0158 14 B0158 13 | -- | -- |
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 applies 5 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 0.05 volts. |
| • | The HVAC control module detects the sensor signal circuit is more than 4.8 volts. |
Action Taken When the DTC Sets
| • | The default value of 15°C (60°F) will be substituted for the ambient air temperature sensor data by the HVAC control module. |
| • | The driver information center (DIC) will display the set temperature when ON. |
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 50 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, engine OFF, with a scan tool observe the Ambient Air Temperature Sensor parameter through the DIC. The reading should be the ambient temperature . If the display of the DIC for temperature reads dashes, check for a sensor signal circuit fault.
Circuit/System Testing
- Ignition OFF, disconnect the ambient air temp sensor harness connector at the ambient air temp sensor terminal A.
- Test for less than 1.0 ohm between the low reference circuit terminal B and ground.
- Ignition ON, test for 5 volts between the low reference circuit terminal B and the 5-volt reference signal terminal A.
- If all circuits test normal, replace the ambient air temperature sensor.
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module. |
| ⇒ | If not the specified voltage, test the signal circuit for a short to voltage, short to ground or open/high resistance. If the circuit tests normal, replace the HVAC control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for HVAC control module replacement, setup, and programming |
