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 C0615 08: Left Front Position Sensor Circuit - Signal Invalid

DTC C0615 55: Left Front Position Sensor Circuit - Expected Number Of Transitions Not Reached

DTC C0620 08: Right Front Position Sensor Circuit - Signal Invalid

DTC C0620 55: Right Front Position Sensor Circuit - Expected Number Of Transitions Not Reached

DTC C0625 08: Left Rear Position Sensor Circuit - Signal Invalid

DTC C0625 55: Left Rear Position Sensor Circuit - Expected Number Of Transitions Not Reached

DTC C0630 08: Right Rear Position Sensor Circuit - Signal Invalid

DTC C0630 55: Right Rear Position Sensor Circuit - Expected Number Of Transitions Not Reached

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left Front Strut Position Sensor 5-Volt Reference

C0696 00

C0615 08

C0696 00

--

Left Front Strut Position Sensor Signal

C0615 08

C0615 08

C0615 08, C0696 00

C0615 55

Left Front Strut Position Sensor Low Reference

--

C0615 08

--

--

Right Front Strut Position Sensor 5-Volt Reference

C0696 00

C0620 08

C0696 00

--

Right Front Strut Position Sensor Signal

C0620 08

C0620 08

C0620 08, C0696 00

C0620 55

Right Front Strut Position Sensor Low Reference

--

C0620 08

--

--

Left Rear Strut Position Sensor 5-Volt Reference

C0696 00

C0625 08

C0696 00

--

Left Rear Strut Position Sensor Signal

C0625 08

C0625 08

C0625 08, C0696 00

C0625 55

Left Rear Strut Position Sensor Low Reference

--

C0625 08

--

--

Right Rear Strut Position Sensor 5-Volt Reference

C0696 00

C0630 08

C0696 00

--

Right Rear Strut Position Sensor Signal

C0630 08

C0630 08

C0630 08, C0696 00

C0630 55

Right Rear Strut Position Sensor Low Reference

--

C0630 08

--

--

Circuit/System Description

The electronic suspension control (ESC) module supplies a 5-volt reference signal to each suspension position sensor. The suspension position sensors supply a signal of 0.35-4.75 volts to the ESC module which represents the position between the body and the wheel. The sensors are also grounded through the ESC module.

Conditions for Running the DTC

    • Battery voltage is between 9-16 volts.
    • Ignition is ON.

Conditions for Setting the DTC

    • The DTC is set when the ESC module measures a position sensor signal less than 0.35 volt or greater than 4.75 volts for more than 1 second while the vehicle is operated under normal driving conditions.
    • The fault is detected during 3 consecutive ignition cycles, or during the same ignition cycle after clearing the DTC with a scan tool.

Action Taken When the DTC Sets

    • The ESC will enter the speed dependent damping mode.
    • Both left and right normal force outputs will be set to the default output states.
    • The ESC sends a message to the instrument panel cluster (IPC) to display SERVICE SUSPENSION SYSTEM message.

Conditions for Clearing the DTC

A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

Reference Information

Schematic Reference

Electronic Suspension Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Suspension Control 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 scan tool Position Sensor Data parameters while the vehicle is jounced. The readings should vary between 0.35-4.75 volts.

Circuit/System Testing

    Important: Whenever repairing and/or replacing ALC system components, perform the Suspension Position Calibration procedure.

  1. Ignition OFF, disconnect the harness connector at the appropriate suspension position sensor.
  2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal C and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If circuit tests normal, replace the ESC module.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.
  5. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ESC module.
    If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ESC module.
  6. Verify the scan tool position sensor parameter is less than 0.35 volts.
  7. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ESC module.
  8. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Position Sensor parameter is greater than 4.75 volts.
  9. If less than the specified range, test the signal circuit for a short to ground or an open high resistance. If all circuits test normal replace the ESC module.
  10. If all circuits test normal, test or replace the suspension position sensor.

Component Testing

  1. Install a 3A fused jumper wire between the 5-volt reference terminal A and 5 volts. Install a jumper wire between the low reference terminal C and ground.
  2. Sweep the suspension position sensor through the entire range while monitoring the voltage between the signal terminal B and the low reference terminal C. The range should vary between 0.35-4.75 volts without any spikes or dropouts.
  3. If not within the specified range or if it is erratic, replace the suspension position sensor.

Repair Instructions

    •  Electronic Suspension Front Position Sensor Replacement
    •  Electronic Suspension Rear Position Sensor Replacement
    •  Suspension Position Calibration
    •  Control Module References for ESCM replacement, setup, and programming

Repair Verification

  1. Install any components or connectors that have been removed or replaced during diagnosis.
  2. Perform any adjustment, programming or setup procedures that are required when a component or module is removed or replaced.
  3. Clear the DTCs.
  4. Use the scan tool Diagnostic Counter Reset output control function to bypass the 3 consecutive ignition cycle requirement for setting a DTC. This will ensure that if a DTC was to be reset during the repair verification process, it will be displayed on the scan tool.
  5. Turn OFF the ignition for 60 seconds.
  6. Turn ON the ignition.
  7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if appropriate, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.