For 1990-2009 cars

### Circuit Description

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. The BCM monitors the voltage drop across the Outside air temperature sensor and uses the input for automatic control calculations. When the outside air temperatures are cold, the resistance of the sensors are high and the voltage signals are high. When the air temperatures are hot, the resistance of the sensors are low and the voltage signals are low. The BCM converts the voltage value to a temperature value of Celsius and Fahrenheit to be displayed by the driver information center (DIC).

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B0158 Outside Air Temperature Sensor

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
01 | Short to Battery or Open
02 | Short to Ground or Open

### Conditions for Running the DTC

The ignition is turned ON.

### Conditions for Setting the DTC

The BCM detects the sensor signal circuit is less than 0.4-volt or more than 4.8 volts.

### Conditions Taken When the DTC Sets

• | The default value of 3°C (38°F) will be substituted for the outside air temperature sensor data by the BCM.

• | The DIC will display the set temperature when ON.

### Conditions for Clearing the DTC

• | The DTC will become history if the BCM no longer detects a failure.

• | The history DTC will clear after 40 fault-free ignition cycles.

• | The DTC can be cleared by using a scan tool.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The operating range of the sensor is between 0.4-4.8 volts. If the DMM displays a value less than 0.4 volt or greater than 4.8 volts, then the sensor is performing outside of its designed limits.

2. Tests for the proper operation of the circuit in the high voltage range.

3. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.

4. Test the signal circuit for a short to ground.

5. Tests the signal circuit for a short to voltage, a high resistance, or an open.

6. Tests the low reference circuit for a high resistance or an open.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a digital multimeter.
2. Turn ON the ignition, with the engine OFF.
3. With a DMM, observe the Outside Air Temperature Sensor signal circuit.

Does the DMM indicate that the Temperature Sensor signal parameter is within the specified range?

0.4-4.8 V

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the outside air temperature sensor.
3. Turn ON the ignition, with the engine OFF.
4. With a DMM, observe the Outside Air Temperature Sensor signal circuit.

Does the DMM indicate that the temperature sensor parameter is more than the specified value?

4.8 V

Go to Step 4

Go to Step 5

4 |

1. Turn OFF the ignition.
2. Connect a 3-amp fused jumper wire between the outside air temperature sensor signal circuit and the low reference circuit of the outside air temperature sensor.
3. Turn ON the ignition, with the engine OFF.
4. With a DMM, observe the Outside Air Temperature signal parameter.

Does the DMM indicate that the temperature sensor signal parameter is less than the specified value?

0.4 V

Go to Step 8

Go to Step 6

5 | Test the signal circuit of the outside air temperature sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9
6 | Test the signal circuit of the outside air temperature sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 7
7 | Test the low reference circuit of the outside air temperature sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9
8 | Inspect for poor connections at the harness connector of the outside air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10
9 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11
10 | Replace the outside air temperature sensor. Refer Ambient Air Temperature Gage Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | --
11 | Important: Perform the recalibration procedure for the body control module after the replacement procedure. Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | --
12 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK