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. |
DTC Descriptor
DTC 023: Excessive Compressor ActivityDiagnostic Fault Information
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 | ||||
Circuit/System Description
The automatic level control sensor monitors for excessive compressor activity and the compressor has been running for 255 seconds during a leveling function.
Conditions for Running the DTC
Ignition is ON.
Conditions for Setting the DTC
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.
Action Taken When the DTC Sets
| • | The automatic level control sensor disables the leveling functions. |
| • | The automatic level control sensor disables the inflator functions. |
Conditions for Clearing the DTC
The conditions that caused the DTC have been removed.
Diagnostic Aids
| • | 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. |
Reference Information
Schematic Reference
Automatic Level Control Schematics
Connector End View Reference
Description and Operation
Automatic Level Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
The automatic level control compressor runs longer than 255 seconds during the leveling function.
Circuit/System Testing
- Ignition OFF, disconnect the automatic level control compressor relay.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
- Disconnect the harness connector at the automatic level control sensor.
- Test for less than 5.0 ohms between the ground circuit terminal A and ground.
- Connect the harness connector at the automatic level control sensor.
- Connect a 3A fused jumper wire between the B+ circuit relay terminal 30 and the relay control circuit terminal 87. Verify the automatic level control sensor is activated.
- Connect a test lamp between the relay B+ circuit terminal 86 and the relay control circuit terminal 85.
- Press the automatic level control switch ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.
- Connect a test lamp between the relay B+ circuit terminal 86 and the ALC compressor ground circuit terminal G.
- Press the accessory inflator switch ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the automatic level control sensor.
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the automatic level control compressor relay.
- Test for 0-2 ohms between terminals 85 and 86.
- Test for infinite resistance between the following terminals:
- Install a 3A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
| ⇒ | 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. |
Repair Instructions
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 |
