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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Suspension 🢒 Automatic Level Control 🢒 Automatic Level Control System Operation Check

Automatic Level Control System Operation Check w/o Road Sensing Suspension

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Turn the ignition switch to the ON position.

After approximately 35-55 seconds, the air compressor runs for 3-5 seconds. NOTE: This action may be overridden by the height sensor if a load has been added or removed from the vehicle.
    • The air compressor cycles on and off frequently. If no air leaks are present, go to Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged strut. If OK, go to Rear of Vehicle Low .

2

Add a 300 lb. load to the luggage compartment.

After a 17-27 second delay, the air compressor runs and the rear of the vehicle rises to the correct trim height. Refer to Trim Height in Suspension General Diagnosis.
    • The air compressor cycles on and off frequently. If no air leaks are present, go to Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged strut. If OK, go to Rear of Vehicle Low .

3

Turn the ignition switch to the OFF position.

Remove the load from the luggage compartment.

After a 17-27 second delay, a hiss of escaping air may be heard, and the rear of the vehicle lowers to the correct trim height. Refer to Trim Height in Suspension General Diagnosis.

The rear of the vehicle remains high. Refer to Rear of Vehicle Low .

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.

Automatic Level Control System Operation Check with Road Sensing Suspension

Step

Action

Normal Result(s)

Abnormal Result(s)*

1
  1. Turn the ignition ON with the engine off.
  2. Clear the CVRSS codes. Refer to Clearing DTCs .
  3. Wait for 90 seconds.
  4. Check for CVRSS codes using the On-Board Diagnostics. Refer to Displaying Diagnostic Trouble Codes (DTC) .

No CVRSS codes are present.

One of the following DTCs is displayed as HISTORY or CURRENT:

    • C1735
    • C1736
    • C1737
    • C1738
        If one of the above DTCs is displayed, go to the appropriate diagnostic table.

2

Turn the ignition switch to the ON position.

After a delay, the air compressor runs for 3-5 seconds. NOTE: This action may be overridden if a load has been added or removed from the vehicle.
    • The air compressor cycles on and off frequently. If no air leaks are present, go to Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged strut. If OK, go to Rear of Vehicle Low .

3

Add a 300 lb. load to the luggage compartment.

After a delay, the air compressor runs and the rear of the vehicle rises to the correct trim height. Refer to Trim Height in Suspension General Diagnosis.
    • The air compressor cycles on and off frequently. If no air leaks are present, go to Rear of Vehicle Low .
    • The air compressor runs excessively. Check for a disconnected or damaged air tube or a damaged strut. If OK, go to Rear of Vehicle Low .

4

Turn the ignition switch to the OFF position.

Remove the load from the luggage compartment.

After a delay, a hiss of escaping air may be heard, and the rear of the vehicle lowers to the correct trim height. Refer to Trim Height in Suspension General Diagnosis.

The rear of the vehicle remains high. Refer to Rear of Vehicle High .

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.