GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Automatic Level Control Sensor monitors the internal hardware and software calibrations of the EEPROM.

Conditions for Running the DTC

The ignition is on.

Conditions for Setting the DTC

The Automatic Level Control sensor detects an internal hardware or software error.

Action Taken When the DTC Sets

The LEVELING indicator lamp will flash while this DTC is present. The function of the ALC system may be degraded or disabled, depending upon which error has been detected.

Conditions for Clearing the DTC

The DTC will clear when no error is detected and the cause for the error has been repaired.

Diagnostic Aids

    • Inspect for the addition of any aftermarket components.
    • inspect all wiring carefully for chaffing and proper routing. Refer toin Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests for all DTCs that are present.

  2. Tests for the proper operation of the system.

Step

Action

Yes

No

Schematic Reference: Automatic Level Control Schematics

1

Did you perform the Automatic Level Control Diagnostic System Check?

Go to Step 2

Go to

Diagnostic System Check - Automatic Level Control

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, check for DTC 001.

Is any other DTCs present?

Go to

Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, check for DTC 001.

Is DTC 001 still present?

Go to Step 4

Go to Step 5

4

Replace Automatic Level Control Sensor. Refer to Automatic Level Control Sensor Replacement .

Did you complete the replacement?

Go to Step 5

--

5

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to

Diagnostic System Check - Automatic Level Control