• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Automatic Level Control (ALC) Inflator Solenoid Valve B+ | 1 | 1 | -- | -- |
Automatic Level Control (ALC) Inflator Solenoid Control | -- | 1 | -- | -- |
1. Automatic Level Control (ALC) Solenoid Valve Inoperative |
Review the automatic level control (ALC) system Description and Operation. Refer to Automatic Level Control Description and Operation .
Automatic Level Control Schematics
Control Module References for scan tool information
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.
⇒ | 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. |
⇒ | 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. |
⇒ | 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. |
⇒ | If not within the specified range, replace the ALC air inflator solenoid. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.