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 B0159: Outside Air Temperature Sensor Circuit Range/Performance

DTC B0164: Passenger Compartment Temperature Sensor 1 Circuit Range/Performance

DTC B0174: Output Air Temperature Sensor 1 Circuit Range/Performance (upper left)

DTC B0179: Output Air Temperature Sensor 2 Circuit Range/Performance (lower left)

DTC B0510: Output Air Temperature Sensor 3 Circuit Range/Performance (upper right)

DTC B0515: Output Air Temperature Sensor 4 Circuit Range/Performance (lower right)

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Inside Air Temperature Sensor Blower Ignition

1

1

--

--

Ambient Air Temperature Sensor Signal

B0159

B0159

B0159

--

Inside Air Temperature Sensor Signal

B0164

B0164

B0164

--

Upper Left Air Temperature Sensor Signal

B0174

B0174

B0174

--

Upper Right Air Temperature Sensor Signal

B0510

B0510

B0510

--

Lower Left Air Temperature Sensor Signal

B0179

B0179

B0179

--

Lower Right Air Temperature Sensor Signal

B0515

B0515

B0515

--

Inside Air Temperature Sensor Blower Control

1

1

1

--

Ambient Air Temperature Low Reference

--

B0159

--

--

Inside Air Temperature Low Reference

--

B0164

--

--

Upper Left Air Temperature Low Reference

--

B0174

--

--

Upper Right Air Temperature Low Reference

--

B0510

--

--

Lower Left Air Temperature Low Reference

--

B0179

--

--

Lower Right Air Temperature Low Reference

--

B0515

--

--

1. Inside air temperature sensor malfunction

Circuit/System Description

The HVAC control module monitors air temperature through air temperature sensors. When the air is cold, the sensor resistance and signal voltage are high. When the air is warm, the sensor resistance and signal voltage are low. The HVAC control module requests A/C compressor clutch engagement and controls the appropriate mode and air temperature actuator door positions in order to maintain the selected air temperature on the HVAC control module.

The inside air temperature sensor provides the HVAC control module with the temperature of the air drawn through an aspirator from the passenger compartment across a sensor. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases and the voltage signal decreases. As the air temperature decreases, the resistance increases and the voltage signal increases.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The HVAC control module detects the air temperature sensor signal circuit is less than 2 counts or greater than 253 counts for 30 seconds.

Action Taken When the DTC Sets

A default value will be used for the sensor data by the HVAC control module.

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

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Air Temperature Description and Operation
    •  Air Delivery 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 Testing

B0159, B0174, B0179, B0510, B0515

  1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
  2. Ignition OFF, test for less than 10.0 ohms between the low reference circuit terminal B and ground.
  3. 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 Temp. Sensor parameter is greater than 250 counts.
  5. If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
  6. Install a 3A fused jumper wire between the signal circuit terminal A and ground. Verify the appropriate scan tool Temp. Sensor parameter is less than 5 counts.
  7. If greater 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 temperature sensor.

B0164

  1. Ignition OFF, disconnect the harness connector at the inside air temperature sensor.
  2. Ignition OFF, test for less than 10.0 ohms between the low reference circuit terminal 3 and ground.
  3. 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 scan tool Inside Air Temp. Sensor parameter is greater than 250 counts.
  5. If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module.
  6. Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Inside Air Temp. Sensor parameter is less than 5 counts.
  7. If greater 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 inside air temperature sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Duct Air Temperature Sensor Replacement - Upper Right Side
    •  Duct Air Temperature Sensor Replacement - Upper Left Side
    •  Duct Air Temperature Sensor Replacement - Lower Left Side
    •  Duct Air Temperature Sensor Replacement - Lower Right Side
    •  Ambient Air Temperature Sensor Replacement
    •  Inside Air Temperature Sensor Replacement
    •  Control Module References for HVAC control module replacement, setup, and programming