GM Service Manual Online
For 1990-2009 cars only

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 B0160: Outside Air Temperature (OAT) Sensor Signal Circuit Low

DTC B0161: Outside Air Temperature Sensor Signal Circuit Open

DTC B0161: Outside Air Temperature Sensor Signal Circuit High

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Ambient Air Temperature Sensor Signal

B0160

B0161

B0161

Ambient Air Temperature Sensor Low Reference

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B0161

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Circuit/System Description

The instrument panel cluster (IPC) monitors the signal circuit of the ambient air temperature sensor. The ambient air temperature sensor is a thermistor which varies in resistance as the temperature changes. As the resistance of the ambient air temperature sensor increases, the IPC senses a larger voltage drop across the sensor, indicating a lower temperature. As the resistance of the ambient air temperature sensor decreases, the IPC senses a smaller voltage drop across the sensor, indicating a higher temperature. The ambient air temperature is displayed in the DIC by the IPC. The ambient air temperature sensor is interfaced with the IPC via the ambient air temperature signal circuit and the low reference circuit.

Conditions for Running the DTC

The IPC must be fully operational within a continuous voltage supply of 9-16 volts.

Conditions for Setting the DTC

B0160

Sets when the instrument panel cluster (IPC) detects that the ambient air temperature is greater than 190°F (88°C) for more than 2 seconds.

B0161

Sets when the IPC detects that the ambient air temperature is less than -40°F (-40°C) for more than 2 seconds.

Action Taken When the DTC Sets

    • "SC" is displayed in the DIC by the IPC when the ambient air temperature sensor resistance value is less than the lowest ambient air temperature sensor resistance threshold and DTC B0160 is present.
    • "OC" is displayed in the DIC by the IPC when the ambient air temperature sensor resistance value is greater than the highest ambient air temperature sensor resistance threshold and DTC B0161 is present.

Conditions for Clearing the DTC

    • The DTC becomes history when the DIC no longer detects a failure.
    • The history DTC clears after 100 fault-free ignition cycles.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the ambient air temperature sensor.
  2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal B and ground.
  3. If greater than the specified value, test the low reference circuit terminal B for an open/high resistance. If the circuit tests normal, replace the IPC.
  4. Ignition ON, verify the driver information center (DIC) displays "OC".
  5. If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the IPC.
  6. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the DIC displays "SC".
  7. If not the specified value, test the signal circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  8. If all circuits test normal, test or replace the ambient air temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ambient Air Temperature Sensor Replacement
    •  Control Module References for the IPC replacement, programming and setups