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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Selective Ride Control Switch Signal Circuit

2

1

1

--

Selective Ride Control Switch Ground Circuit

--

1

--

--

  1. Ride Always Soft
  2. Ride Always Firm

Circuit/System Description

The electronic suspension control (ESC) module utilizes the suspension position sensor signals to control the suspension dampers . When the driver selects the SPORT position on the suspension control switch, a ground signal is sent to the body control module (BCM). The BCM then sends a serial data signal to the ESC module requesting a firmer damper ride control rate for each damper allowing the driver to customize the ride and handling of the vehicle.

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, with the scan tool, observe each Position Sensor data parameter while jouncing the vehicle at each corner. The corresponding parameters should fluctuate with each action.

If a parameter does not fluctuate or is erratic, test or replace the position sensor associated with that parameter.

Ignition ON, with the scan tool, observe the Ride Handling Sw. data parameter in the BCM Chassis data list while toggling the suspension control switch between the TOURING and SPORT positions. The parameter should change state.

If the parameter does not change state , refer to Circuit/System Testing.

Circuit/System Testing

  1. Ignition OFF, disconnect the suspension control switch.
  2. Test for less than 2 ohms between the switch harness connector terminal 3 and ground.
  3. If greater than the specified value, repair the open/high resistance.
  4. Ignition ON, use a fused jumper to apply and unapply ground at the switch harness connector terminal 2 while observing the Ride Handling Sw. data parameter in the BCM Chassis data list.
  5. If the parameter does not switch between states, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. Test or replace the suspension control switch.

Component Testing

Suspension Control Switch

  1. Place the suspension control switch in the TOUR position.
  2. Test for infinite resistance between terminal 2 and terminal 3.
  3. If less than the specified value, replace the switch.
  4. Place the suspension control switch in the SPORT position.
  5. Test for less than 2 ohms between terminal 2 and terminal 3.
  6. If greater than the specified value, replace the switch.

Suspension Position Sensor

  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 applicable suspension position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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