Schematic Reference: Automatic Level Control Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

1. Turn ON the ignition with the engine OFF.
2. Listen for the automatic level control (ALC) air compressor to activate.

Does the air compressor come on within 30 seconds?

Go to Step 8

Go to Step 3

1. Turn OFF the ignition.
2. Disconnect the ALC connector from the ALC air compressor assembly.
3. Disconnect the electronic suspension module connector.
4. Turn ON the ignition.
5. Connect a fused jumper between the ALC relay coil supply voltage circuit and ground.
6. Measure the voltage between the ALC compressor motor control circuit and ground.

Does the voltmeter display a voltage greater than 10 volts?

Go to Step 4

Go to Step 6

1. Remove the fused jumper wire.
2. Turn OFF the ignition.
3. Test the ground circuit of the ALC air compressor connector for a ground.

Did you find and correct the condition?

Go to Step 13

Go to Step 5

Replace the ALC air compressor assembly. Refer to Air Compressor Replacement .

Is the repair complete?

Go to Step 11

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1. Remove the fused jumper wire.
2. Turn OFF the ignition.
3. Inspect for the following:

•	An open electronic level control (ELC) fuse

•	A bad ELC relay

•	An open circuit in ALC air compressor motor control circuit

•	An open circuit in ALC relay coil supply voltage circuit

Was a problem found?

Go to Step 7

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Important: An open fuse may indicate:

Repair the short to ground in the ALC compressor battery positive circuit or replace the fuse.

Is the repair complete?

Go to Step 13

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Inspect the left and right rear position sensors for damage and disconnected links.

Are any damaged sensors or disconnected links present?

Go to Step 12

Go to Step 9

Perform the ALC System Leak Test. Refer to Air Compressor Leak Test

Is a leak present?

Go to Step 10

Go to Step 11

Repair the leak in the ALC System.

Is the repair 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 engine OFF.
4. Perform the ESC/ALC recalibration procedure. Refer to Electronic Suspension Control Module Programming and Setup in Vehicle Control Systems.

Has the recalibration been completed?

Go to Step 13

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Replace the damaged rear position sensor or reconnect the link.

Is the replacement complete?

Go to Step 13

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1