For 1990-2009 cars

### Test Description

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

1. Lack of communication may be due to a malfunction of the Keyword serial data circuit. The specified procedure will determine the particular condition

Step | Action | Yes | No
--- | --- | --- | ---
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 Automatic Level Control (ALC) sensor.

Does the scan tool communicate with the ALC sensor?

Go to Step 3

Go to Scan Tool Does Not Communicate with Automatic Level Control Sensor in Data Link Communications

3 | Select the Leveling Sensor DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Diagnostic Trouble Code (DTC) List/Type | Go to Automatic Level Control Symptoms