Circuit Description
The exhaust valve is controlled by the Automatic Level Control (ALC) sensor. The sensor provides a low side drive whenever exhaust activity is required and during a 'head-relief' sequence, which occurs before each compressor start up. This drive output from the sensor is continually monitored to determine if the voltage level agrees with the commanded state.
Conditions for Setting the DTC
The sensor detects that the valve output is not pulling down to ground when the sensor output is activated.
Action Taken When the DTC Sets
| • | The sensor flashes the LEVELING indicator lamp. |
| • | The sensor's discrete low side output drive for the valve is disabled. |
| • | The sensor contentiously attempts to recover from the fault. |
| • | DTC 07 is stored as a history code at the end of the ignition cycle. |
Conditions for Clearing the DTC
| • | The DTC will clear when B+ is present at the low side output drive. |
| • | Using a scan tool. |
Diagnostic Aids
| • | Perform the system leak test. Refer to Automatic Level Control System. |
| • | Refer to the diagnostic table. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Automatic Level Control (ALC) System Check performed? | -- | Go to ALC Suspension System Check . | |
Is the voltage reading within the specified value? | B+ | |||
3 | Locate and repair a short to B+ in circuit M101. Is the repair complete? | -- | -- | |
Use a DMM in order to measure the resistance between terminal A and terminal C of the compressor connector. Is the resistance reading with the specified value? | 25 ohms-35 ohms | Perform the system leak test. Go to Automatic Level Control. | ||
5 |
Is the LEVELING indicator lamp flashing? | -- | ||
6 | Replace the ALC sensor. Refer to Automatic Level Control in Suspension. Is the replacement complete? | -- | -- | |
7 |
Is the rear of the vehicle level? | -- | System OK |
