Diagnostic System Check - Rear Axle Controls: Testing

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Check for applicable service bulletins before proceeding with this test. Perform this test only if there is a driveability complaint or if you have been directed to this table from another section in the service information. Do not turn the ignition OFF when performing this diagnostic procedure. Do not clear the DTCs unless instructed by this diagnostic procedure.

NOTE: This step determines if the scan tool is receiving power through the DLC connector.

Install a scan tool. Turn ON the ignition, with the engine OFF. Does the scan tool turn ON? If so go to next step. If not, go to SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article.

NOTE: This step determines if the PCM is transmitting class 2 serial data to the DLC and that the Class 2 data circuit is not open or shorted.

Attempt to establish communication with the PCM. Does the scan tool communicate with the PCM? If so go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article.

NOTE: The presence of DTCs indicates that the powertrain control module has detected a fault. Go to symptoms for other concerns.

Select the powertrain control module display DTCs function on the scan tool. Does the scan tool display any DTCs? If so go to next step. If not go to SYMPTOMS - REAR AXLE CONTROLS .

NOTE: This step determines if a DTC is current or stored in history.

Does the scan tool display any DTCs which begin with a "U"? If so go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article. If not, go to appropriate SELF DIAGNOSTICS in FAULT ISOLATION under ENGINE PERFORMANCE.