Step 
 | Action 
 | Yes 
 | No 
 | 
Schematic Reference: 
Automatic Level Control Schematics 
 | 
1 
 | Did you perform the Diagnostic System Check - Vehicle? 
 | Go to 
Step 2
  
 | Go to 
Diagnostic System Check - Vehicle 
 | 
2 
 | 
- Turn the ignition ON, with the engine OFF.
 
- Listen for the automatic level control (ALC) air compressor to activate.
 
 
Is the ALC air compressor running for more than 5 minutes? 
 | Go to 
Step 3
  
 | Go to 
Step 6
  
 | 
3 
 | 
- Turn the ignition OFF.
 
- Remove the ALC compressor relay.
 
- Turn the ignition ON, with the engine OFF.
 
 
Is the air compressor running? 
 | Go to 
Step 4
  
 | Go to 
Step 5
  
 | 
4 
 | 
- Turn the ignition OFF.
 
- Reinstall the ALC compressor relay.
 
- Repair the short to voltage in the ALC air compressor motor control circuit.
 
 
Is the repair complete? 
 | Go to 
Step 13
  
 | -- 
 | 
5 
 | 
- Turn the ignition OFF.
 
- Replace the ALC air compressor relay.
 
 
Is the repair complete? 
 | Go to 
Step 13
  
 | -- 
 | 
6 
 | Inspect the left and right rear position sensors for damage and disconnected links. 
Are any damaged sensors or disconnected links present? 
 | Go to 
Step 7
  
 | Go to 
Step 8
  
 | 
7 
 | Replace the damaged rear position sensor or reconnect the link. 
Is the repair complete? 
 | Go to 
Step 13
  
 | -- 
 | 
8 
 | 
- Remove the ALC intake filter from the vehicle body. Do not remove it from the ALC air compressor or hose.
 
- Using the scan tool, cycle ALC air compressor.
 
- After 1 minute, stop cycling.
 
- Cycle the ALC exhaust solenoid while checking to see if air is exiting the ALC intake air filter.
 
 
Is air exiting the ALC intake air filter? 
 | Go to 
Step 11
  
 | Go to 
Step 9
  
 | 
9 
 | 
- Disconnect the air tubes from both rear shock absorbers.
 
- Connect the 
J 22124-B 
 ALC Pressure Gage between both air tubes.
 
- Open the gage toggle valve.
 
- Disconnect the air tube from the ALC air dryer.
 
- Apply shop air to the gage schrader valve.
 
 
Is air exiting both of the air tubes at the ALC air dryer connection? 
 | Go to 
Step 10
  
 | Go to 
Step 12
  
 | 
10 
 | 
- Turn the ignition OFF.
 
- Replace the ALC air compressor assembly. Refer to 
Air Compressor Replacement
 .
 
- Install the ALC intake air filter on the vehicle body.
 
 
Are all of the replacements and/or installations complete? 
 | Go to 
Step 13
  
 | -- 
 | 
11 
 | 
- Turn the ignition OFF.
 
- Connect the scan tool.
 
- Turn the ignition ON with the engine OFF.
 
- Perform the ESC/ALC recalibration procedure. 
 
 
Has the recalibration procedure been completed? 
 | Go to 
Step 13
  
 | -- 
 | 
12 
 | Replace the air tube going from the air dryer to both rear shock absorbers. Refer to 
Air Tube Replacement
 . 
Is the repair complete? 
 | Go to 
Step 13
  
 | -- 
 | 
13 
 | 
- Turn the ignition OFF.
 
- Turn the ignition ON with the engine OFF.
 
- Wait for at least 5 minutes.
 
 
Is the rear of the vehicle at trim level? 
 | Go to 
Step 14
  
 | Go to 
Step 2
  
 | 
14 
 | Operate the system in order to verify the repair. 
Did you correct the condition? 
 | System OK 
 | Go to 
Step 2
  
 |