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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 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 Diagnostics.
    • 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 Diagnostics.

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* 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 Diagnostics.
    • 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 Diagnostics.

--

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