For 1990-2009 cars

### 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. The presence of DTCs which begin with a "U" indicate some other module is not communicating on the class 2 serial data circuit. The specified procedure will compile all the available information before tests are performed.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Instrument Cluster 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 the ignition ON, with the engine OFF.
2. Attempt to establish communication with the following control modules:

• | Body Control Module (BCM)

• | Electronic Brake Control Module (EBCM)

• | Inflatable Restraint Sensing and Diagnostic Module (SDM)

• | Instrument Panel Cluster (IPC)

• | Powertrain Control Module (PCM)

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

Go to Step 3

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

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

• | Body Control Module (BCM)

• | Electronic Brake Control Module (EBCM)

• | Inflatable Restraint Sensing and Diagnostic Module (SDM)

• | Instrument Panel Cluster (IPC)

• | Powertrain Control Module (PCM)

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Instrument Panel, Gages and Console

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, B1001, B1369, B1374, or B1379? | Go to Diagnostic Trouble Code (DTC) List in Body Control System | Go to Step 6
6 | Does the scan tool display DTC P0562, P0563, P0621, or P0622? | Go to Diagnostic Trouble Code (DTC) List in Engine Electrical | Go to Diagnostic Trouble Code (DTC) List