• | 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 |
---|---|---|---|---|
Relay Coil B+ | 023 | 1 | -- | -- |
Relay Switch B+ | -- | 1 | -- | -- |
Relay Coil Control | 023 | 023 | 023 | -- |
Relay Controlled Output | 2 | 2 | 3 | -- |
Automatic Level Control (ALC) Compressor Ground | -- | 023 | -- | -- |
1. Automatic Level Control (ALC) Compressor Relay Inoperative 2. Automatic Level Control (ALC) Sensor Relay Control Inoperative 3. Automatic Level Control (ALC) Sensor Relay Control Always ON |
The automatic level control sensor monitors for excessive compressor activity and the compressor has been running for 255 seconds during a leveling function.
Ignition is ON.
The DTC is set when the automatic level control sensor detects the compressor relay coil control circuit is shorted to ground, open, or shorted to voltage.
• | The automatic level control sensor disables the leveling functions. |
• | The automatic level control sensor disables the inflator functions. |
The conditions that caused the DTC have been removed.
• | An AIR LEAK in the system will cause this DTC to set. |
• | If the rod is disconnected, DTC 033 will be set. |
• | Inspect all air lines and exhaust valves for air leakage. Check both rear shock absorbers for air leakage. |
Automatic Level Control Schematics
Automatic Level Control Description and Operation
Control Module References for scan tool information
The automatic level control compressor runs longer than 255 seconds during the leveling function.
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
⇒ | 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 control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the automatic level control compressor relay. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the automatic level control sensor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the automatic level control sensor. |
⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the automatic level control sensor. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the automatic level control sensor. |
⇒ | If the test lamp is always ON, test or replace the compressor motor. |
⇒ | If the test lamp is always OFF, test the compressor ground circuit for an open. If the circuit tests normal, test or replace the ALC relay. |
⇒ | If the resistance is not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Important: System untested codes will continue to flash until self test has been completed after automatic level control sensor replacement.
• | Control Module References for automatic level control sensor replacement, setup, and programming |