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 Descriptor

DTC 002: Left Rear Position Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Air Suspension Compressor Assembly Battery Positive Voltage

1, 2, 4, 6

1, 2, 4, 6

--

--

Air Suspension Compressor Assembly Ignition 3 Voltage

1, 2, 4, 6

1, 2, 4, 6

--

--

Air Suspension Compressor Assembly Ground

--

1, 2, 4, 6

--

--

Air Suspension Inflator Switch Ground

--

4, 6

--

--

Air Suspension Inflator Switch Indicator Control

4

4

3

--

Air Suspension Inflator Switch Signal

5

6

6

--

Left Rear Air Suspension Sensor Low Reference

--

DTC 002

--

--

Left Rear Air Suspension Sensor Signal

DTC 002

DTC 002

DTC 002

--

Right Rear Air Suspension Sensor Low Reference

--

DTC 003

--

--

Right Rear Air Suspension Sensor Signal

DTC 003

DTC 003

DTC 003

--

Vehicle Speed Signal

B0540

7

B0540

--

1. Air Springs Do Not Deflate

2. Air Springs Do Not Inflate

3. Air Suspension Inflator Switch Indicator Always ON

4. Air Suspension Inflator Switch Indicator Inoperative

5. Inflator Always ON

6. Inflator Inoperative

7. Inflator Will Operate While Vehicle is in Motion

Circuit/System Description

The left rear air suspension sensor arm is attached to an armature that rotates inside a coil. The air suspension compressor assembly determines the angle of the sensor arm by measuring the voltage of the left rear air suspension sensor signal at 50 ms intervals via the left rear air suspension sensor signal circuit.

Conditions for Running the DTC

    • Battery voltage is between 9-16 volts.
    • The ignition is ON for 30 seconds.

Conditions for Setting the DTC

The air suspension compressor assembly detects a invalid height sensor signal.

Action Taken When the DTC Sets

    • The air suspension compressor assembly shall disregard the left rear air suspension sensor input and use the right rear air suspension sensor to determine the vehicle height.
    • If both air suspension sensor DTCs are set, the air suspension compressor assembly shall deactivate the compressor, corner solenoids, and exhaust solenoids. All leveling functions will be disabled. Inflator functions will not be disabled.

Conditions for Clearing the DTC

The DTC will automatically clear when the condition for setting the DTC is removed.

Reference Information

Schematic Reference

Air Suspension Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Air Suspension Description and Operation

Electrical Information Reference

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

Circuit/System Verification

Ignition ON, load the vehicle with additional weight in the rear. The air suspension compressor should activate raising the vehicle to the calibrated vehicle level. Remove the additional load and the compressor will exhaust the necessary amount of air to return to the calibrated vehicle level.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the left rear air suspension sensor.
  2. Test for less than 2.0 ohms between the low reference circuit terminal B and ground.
  3. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the air suspension compressor assembly.
  4. Perform the component test on the left rear air suspension sensor.
  5. If the sensor fails the component test, replace the sensor
  6. Test the left rear air suspension signal circuit for an open/high resistance, short to ground, or short to voltage.
  7. If the circuit tests normal, replace the air suspension compressor assembly.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the left rear air suspension sensor.
  2. Test for 75-100 ohms between the signal circuit terminal and the low reference circuit terminal while sweeping the sensor arm through the entire range.
  3. If not within the specified range or if the reading is erratic, replace the sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Air Spring Leveling Sensor Replacement
    •  Automatic Level Control Air Compressor Replacement
    •  Rear Air Spring Level Sensor Calibration