GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 Yukon - 4WD 🢒 Suspension 🢒 Automatic Level Control 🢒 Diagnostic System Check - Automatic Level Control

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

    2.

  2. Check for the presence of DTCs.

    3.

  3. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

    4.

  4. Check for the presence of DTCs in Body Control system.

    5.

  5. Check for the presence of DTCs in Automatic Level Control system.

Step

Action

Yes

No

Schematic Reference: Automatic Level Control Schematics

1

Install a scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not Power Up in Data Link Communications

2

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the suspension control module.

Does the scan tool communicate with the suspension control module?

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

3

Select the suspension control module display DTCs function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Automatic Level Control

4

Does the scan tool display any DTCs which begin with a "U"?

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Step 5

5

Does the scan tool display DTC B1000?

Go to Diagnostic Trouble Code (DTC) List in Body Control System

Go to Step 6

6

Does the scan tool display DTC C0655, C0660, or C0711?

Go to Diagnostic Trouble Code (DTC) List

Go to Diagnostic Trouble Code (DTC) List in Real Time Damping