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 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

B0158 13

B0158 13

B0158 14

1

Inside Air Temperature Sensor Signal

B0163 02

B0163 05

B0163 05

1

Upper Air Temperature Sensor Signal

B0173 02

B0173 05

B0173 05

1

Lower Air Temperature Sensor Signal

B0178 02

B0178 05

B0178 05

1

Left Sunload Sensor Signal

B0183 02

B0183 05

B0183 05

1

Right Sunload Sensor Signal

B0188 02

B0188 05

B0188 05

1

Evaporator Temperature Sensor Signal

B3933 14

B3933 13

B3933 13

1

Low Reference

--

B3933 05, B0158 05, B0163 05

B3933 05, B0158 05, B0163 05

1

Sunload Sensors Ground

--

B0183 05, B0188 05

B0183 05, B0188 05

1

1. Air Temperature Malfunction

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

Ignition 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 greater than 4.9 volts.

Action Taken When the DTC Sets

    • The default value of 85°C (185°F) will be substituted for the ambient air temperature sensor data by the HVAC control module.
    • The DIC will display - -.

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 100 fault-free ignition cycles.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Air Delivery Description and Operation
    •  Air Temperature Description and Operation

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 Verification

Ignition ON, observe the appropriate scan tool Air Temp Sensor parameter. The reading should be between -35 and +85°C (-39 and +185°F) and change with air temperature changes.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate air temperature sensor.
  2. Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal and ground.
  3. • Inside air temperature sensor terminal 2.
    • Ambient temperature sensor terminal B.
    If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  4. Ignition ON, verify the appropriate scan tool Air Temp Sensor parameter is less than -35°C (-39°F).
  5. If greater than the specified range, test the following signal circuit terminal for a short to ground. If the circuit tests normal, replace the HVAC control module.
    • Inside air temperature sensor terminal 1.
    • Ambient temperature sensor terminal A.
  6. Install a 3A fused jumper wire between the following signal circuit terminal and the low reference circuit terminal. Verify the scan tool Air Temp Sensor parameter is greater than 85°C (185°F).
  7. • Inside air temperature sensor terminal  1 and 2.
    • Ambient temperature sensor terminal A and B.
    If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  8. If all circuits test normal, test or replace the air temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ambient Air Temperature Sensor Replacement
    •  Control Module References for HVAC control module replacement, setup, and programming