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 trim height specifications in Suspension General Diagnosis.
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:
- Inspect the ignition (pin A & H) at the ALC sensor connector.
- Ensure the ignition (pin A & H) at the ALC sensor connector connection is secure.
- Inspect the ground (pin E) at the ALC sensor connector.
- Ensure the ground (pin E) at the ALC sensor connector connection is secure.
- Inspect the ALC sensor link.
- Ensure that the ALC sensor link is properly secured to the actuator arm.
- Inspect the ALC sensor actuator arm for damage.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Has the ALC compressor assembly and the air tube been replaced? | -- | ||||||
2 |
Are the air tubes damaged and/or disconnected? | -- | ||||||
3 | Squeeze the left rear shock absorber in the middle of the air sleeve. Did the air sleeve slightly compress? | -- | ||||||
4 |
Is a leak evident? | -- | ||||||
5 |
Did the pressure build to the specified value? | 80 psi | ||||||
6 |
Did the pressure leak down? | -- | ||||||
7 |
Did the system leak down? | -- | ||||||
8 |
Did the pressure leak down? | -- | ||||||
9 |
Did the pressure leak down? | -- | ||||||
10 | Replace the following components:
Are the replacements complete? | -- | -- | |||||
11 |
Is the shock absorber replaced and are all the air tube connections reconnected? | -- | -- | |||||
12 |
Is the shock absorber replaced and are all the air tube connections reconnected? | -- | -- | |||||
13 | Are any of the air tubes damaged? | -- | ||||||
14 | Replace the air tube that runs from the air dryer to the two rear shock absorbers. Refer to Air Tube Replacement . Is the replacement complete? | -- | -- | |||||
15 |
Did water/moisture come out of the ALC air dryer when it was shaken? | -- | ||||||
16 | Replace the ALC air dryer. Refer to Automatic Level Control Air Dryer Replacement . Is the replacement complete? | -- | -- | |||||
17 | Replace the compressor head. Refer to Automatic Level Control Air Compressor Head Replacement . Is the replacement complete? | -- | -- | |||||
18 |
Is the ALC compressor reinstalled and are all the air tube connections reconnected? | -- | -- | |||||
19 | Repair the air tube-to-air dryer connection leak. Is the repair complete? | -- | -- | |||||
20 |
Is the rear of the vehicle trim level? | -- | System OK | -- |
