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 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. The presence of DTCs for other subsystems which share the same control module can cause other subsystem functions to be suspended.

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. Tests if the malfunction exists in the Variable Effort Steering (VES) system.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Steering Assist 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 EBCM.

Does the scan tool communicate with the EBCM?

Go to Step 3

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

3 | Select the VES Diagnostic Trouble Codes (DTC) function on the scan tool. Does the scan tool display ABS/TCS DTCs? | Go to Diagnostic System Check - ABS in Antilock Brake System | Go to Step 4
4 | Does the scan tool display any DTCs which begin with a "U"? | Go to Diagnostic Trouble Code (DTC) List in Data Link Communications | Go to Step 5
5 | Does the scan tool display DTC C1241? | Go to Diagnostic Trouble Code (DTC) List | Go to Symptoms - Power Steering System in Power Steering System