Suspension Control - Automatic Level Control (Alc)

Circuit Description

The consecutive intake register will keep track of the number of times a compress sequence is initiated, without an exhaust sequence, while the vehicle is moving. This allows detection of air leaks when the vehicle is moving.

Conditions for Setting the DTC

When the number of compress sequences is more than 10, without an exhaust sequence.

Action Taken When the DTC Sets

^ All compressor activity is disabled.
^ The LEVELING indicator lamp flashes.
^ DTC 12 is stored as a history code at the end of the ignition cycle.

Conditions for Clearing the DTC

^ Initiation of an exhaust sequence.
^ Cycling the ignition.
^ Using a scan tool.

Diagnostic Aids

Perform the system leak test.

ALC System Operation Check

Support the rear wheels or support the rear lower control arms when certain tests require raising the vehicle on a hoist. Use two additional jack stands to support the rear lower control arms in its normal curb weight position when a frame type hoist is used.

Refer to ALC Suspension System Check for electrical troubleshooting of the Automatic Level Control (ALC) system or if DTC's are present.

Diagnosing Leveling Complaints Without DTCs Present Procedure

Perform the following preliminary inspections before performing the system performance test:

1. Inspect the ignition (pin A & H) at the ALC sensor connector.
2. Ensure the ignition (pin A & H) at the ALC sensor connector connection is secure.
3. Inspect the ground (pin E) at the ALC sensor connector.
4. Ensure the ground (pin E) at the ALC sensor connector connection is secure.
5. Inspect the ALC sensor link.
6. Ensure that the ALC sensor link is properly secured to the actuator arm.
7. Inspect the ALC sensor actuator arm for damage.