Extended Ride Height Switch Indicator Malfunction

Extended Ride Height Switch Indicator Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit Description

The air suspension control module monitors the ride height switch active light emiting diode LED indicator signal for a short to battery.


Conditions for Running the Diagnostic Fault

* Battery voltage is between 9-16 volts.
* The ignition is ON or OFF.



Conditions for Setting the Diagnostic Fault

The air suspension module senses the ride height active indicator light emitting diode LED signal circuit voltage shorted to battery, short to ground, or open.


Action Taken When the Diagnostic Fault

* The air suspension system will be inoperative.
* No message is displayed.



Reference Information
Schematic Reference

Air Suspension Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

Air Suspension Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Programming and Relearning (Programming and Relearning)for Scan Tool Information


Circuit Validation

Ignition ON, Observe the scan tool ERH Switch Indicator parameter while pressing/depressing the ERH Switch. The reading should change between ON and OFF.


Circuit/System Testing

1. Ignition OFF, disconnect the switch harness connector terminal A2 at the automatic suspension control module (ASCM).
2. Ignition ON, verify that a test lamp illuminates between the instrument panel B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the ASCM ride height active signal circuit terminal A2 for a short to ground.

3. Verify the scan tool ERH Switch Indicator parameter is OFF.

• If not the specified value, test the ASCM signal circuit terminal A2 for a short to voltage. If the circuit tests normal, test or replace the air suspension control module (ASCM).

4. Install a 3A fused jumper wire between the signal circuit terminal A2 and the Instrument Panel B+ circuit terminal. Verify the scan tool ERH Switch Indicator parameter is ON.

• If not the specified value, test the ASCM ride height active signal circuit for an open/high resistance. If the circuit tests normal, replace the ASCM.


• If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the ASCM.

5. If all circuits test normal, test or replace the ERH Switch Rear Air Suspension Control Valve Switch in the IP Switch bank.



Component Testing

1. Ignition OFF, disconnect the harness at the ERH switch.
2. Test for infinite resistance between the ride height active indicator control signal circuit terminal A2 and the Instrument Panel B+ circuit terminal 1 with the switch in the open position. (Released)

• If not the specified value, replace the ERH Switch.

3. Test for less than 2 ohms between the signal circuit terminal A2 and the B+ circuit terminal with the switch in the closed position. (Pressed)

• If greater than the specified range, replace the ERH Switch.

4. Test for infinite resistance between each terminal and the ERH Switch housing/case.

• If not the specified value, replace the ERH Switch Rear Air Suspension Control Valve Switch in the IP Switch bank.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Rear Air Suspension Control Valve Switch Replacement (Rear Air Suspension Control Valve Switch Replacement)
* Suspension Position Calibration (Suspension Position Calibration)
* Programming and Relearning (Programming and Relearning)for Air Suspension Control Module replacement, setup and programming