Automatic Level Control Inflator Fill Valve Inoperative

Automatic Level Control Inflator Fill Valve Inoperative

Diagnostic Instructions

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

Diagnostic Fault Information





Diagnostic Aids

Review the automatic level control (ALC) system Description and Operation.

Reference Information
Schematic Reference

Automatic Level Control Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
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

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, Press the accessory inflator switch continuously for 3 seconds, this activates the ALC self test of the rear shocks. The rear of the vehicle will rise, and then hold the rear of the vehicle up for a calibrated amount of time, to check for leaks, and then lower the rear of the vehicle to trim height. The total self test time is 200 seconds.

Circuit/System Testing

1. Ignition OFF, disconnect the air inflator air switch harness connector at the ALC sensor.
2. Ignition ON, Connect a 10A fused jumper wire between the ALC relay inflation timer relay coil control terminal 85 and the ground circuit terminal of the air inflator switch.
3. Verify that a test lamp illuminates between the B+ circuit terminal A 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, test or replace the ALC Compressor Relay.

4. Ignition OFF, disconnect the ALC solenoid valve harness connector at the ALC sensor.
5. Verify that a test lamp illuminates between the ALC solenoid valve B+ circuit terminal B 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, test or replace the ALC solenoid valve.

6. Verify that a test lamp illuminates between the ALC inflator solenoid valve B+ circuit terminal B and the ALC inflator solenoid valve ground terminal A.

• If the test lamp illuminates, test or replace the ALC air inflator solenoid valve.
• If the test lamp does not illuminate, test the ground circuit for open/high resistance.

7. If all circuits test normal, test or replace the air inflator solenoid valve.

Component Testing

1. Ignition OFF, disconnect the ALC solenoid valve harness connector at the automatic level control sensor.
2. Test for 0-2 ohms between the signal terminal B and the low reference circuit terminal A.

• If not within the specified range, replace the ALC air inflator solenoid.

Repair Instructions

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

* Automatic Level Control Relay Replacement (Automatic Level Control Relay Replacement)
* Inflator Solenoid Replacement (Inflator Solenoid Replacement)