Schematic Reference: Automatic Level Control Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Turn ON the ignition, with the engine OFF.
2. 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

1. Turn OFF the ignition.
2. Remove the ALC compressor relay.
3. Turn ON the ignition, with the engine OFF.

Is the air compressor running?

Go to Step 4

Go to Step 5

1. Turn OFF the ignition.
2. Reinstall the ALC compressor relay.
3. Repair the short to voltage in the ALC air compressor control circuit.

Is the repair complete?

Go to Step 13

Go to Step 1

1. Turn OFF the ignition.
2. Replace the ALC air compressor relay.

Is the repair complete?

Go to Step 13

Go to Step 1

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

Replace the damaged rear position sensor or reconnect the link. Refer to Automatic Level Control Sensor Replacement .

Is the repair complete?

Go to Step 13

Go to Step 1

1. Remove the ALC intake filter from the vehicle body. Do not remove it from the ALC air compressor or hose.
2. Using the scan tool, cycle ALC air compressor.
3. After 1 minute, stop cycling.
4. Cycle the ALC exhaust 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

1. Stop exhausting.
2. Disconnect the air tubes from both rear shock absorbers.
3. Connect the J 22124-B ALC Pressure Gage to both (between) air tubes.
4. Open the gage toggle valve.
5. Disconnect the air tube from the ALC air dryer.
6. 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

1. Turn OFF the ignition.
2. Replace the ALC air compressor assembly. Refer to Air Compressor Replacement .
3. Install the ALC intake air filter on the vehicle body.

Are all of the replacements and/or installations complete?

Go to Step 13

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1. Turn OFF the ignition.
2. Connect the scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Perform the ALC relearn procedure. Refer to Body Control Module Programming and Setup .

Has the ALC relearn procedure been completed?

Go to Step 13

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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

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1. Turn OFF the ignition.
2. Turn the ignition ON, with the engine OFF.
3. Wait for at least 5 minutes.

Is the rear of the vehicle trim level?

Go to Step 14

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1