How to Troubleshoot a Chevrolet Lumina PCM

A fault PCM will activate a dashboard's check engine light.

A Chevrolet Lumina's Powertrain Control Module is part of the vehicle's second generation On-Board Diagnostic system. It is the central processor in the OBD-II system. Also, it interacts with sensors throughout the Lumina, cataloging instances of fault and malfunction.

OBD-II Codes

Once the Lumina's PCM detects a problem, it assigns the fault or malfunction an alpha-numeric code. These codes correspond with mechanical definitions that you can either look up online or in a Haynes or Chilton manual for the Lumina's model-year. PCM related problems are among the many codes within the OBD-II spectrum. Essentially, the PCM not only diagnoses powertrain functionality, but it also runs self-diagnostic checks.

Codes to Look For

Drivers may find PCM-related trouble codes in a variety of places. A universal set of generic codes exists that is good for all post-1996 vehicles. General Motors has a separate set of codes for their particular engines. So, Chevrolet, GMC, Buick, Pontiac, and Oldsmobile vehicles all use these supplemental codes. Since the PCM is also an electrical component, the OBD-II Chassis codes also apply. Make a list of all PCM relevant codes before running the Lumina's OBD-II diagnostics.

How to Access the PCM

Connect an OBD-II scanner to the Lumina's Data Link Connection. The DLC outlet can be found beneath the steering column. Turn your scanner on. Turn the Lumina's electrical system on. Depending the brand of scanner, you may also need to crank the engine. Consult the scanner's manual for exact instructions on how to enter a "scan" or "read" command.

Repair Options

If the scanner displays PCM related trouble codes, only a few options exist. The PCM can be rewired, reprogrammed, restarted, or wholly replaced. A home mechanic may want to seriously consider consulting a trained profession. The Lumina's PCM is not an "off the shelf" part like wiper blades, filters, or belts. You may need to order a replacement , and depending on the problem, you may need something more sophisticated then an OBD-II scanner.

References

• "Haynes Repair Manual: General Motors Buick Regal, Chevrolet Lumina,Olds Cutlass Supreme,Pontiac Grand Prix, 1988-2007"; Haynes Publishing Group; 2009
• CarMD: How Do I Find My Vehicle's Connector?
• US EPA: OBD Basics

Resources

• OBD Codes: OBD-II (Check Engine Light) Trouble Codes
• Engine Light Help: Chevy Check Engine Light Codes
• Chevrolet: Owner's Manuals