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 keyword 82 data line circuit or due to a total malfunction of the keyword 82 data line circuit. The specified procedure will determine the particular condition.

2. Lack of communication may be due to a partial malfunction of the keyword 2000 data line circuit or due to a total malfunction of the keyword 2000 data line circuit. The specified procedure will determine the particular condition.

3. The symptom list in Symptoms will determine the correct diagnostic procedure to use.

4. The presence of DTCs which begin with "U" indicate that loss of Class 2 communications has occurred.

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 the ignition ON, with the engine OFF.
2. Attempt to establish communication with the Instrument Panel Cluster (IPC).

Does the scan tool communicate with the control module listed above?

Go to Step 3

Go to Scan Tool Does Not Communicate with Keyword Data Line in Data Link Communications

3 |

1. Turn the ignition ON, with the engine OFF.
2. Attempt to establish communication with the Engine Control Module (ECM).

Does the scan tool communicate with the control module listed above?

Go to Step 4

Go to Scan Tool Does Not Communicate with Keyword Data Line in Data Link Communications

4 | Select the display DTCs function on the scan tool for the following control modules:

• | Instrument Panel Cluster (IPC)

• | Engine Control Module (ECM)

Does the scan tool display any DTCs?

Go to Step 5

Go to Symptoms - Instrument Panel, Gages and Console

5 | Does the scan tool display any other DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Diagnostic Trouble Code (DTC) List