After 1996, all makes and models sold in the United States featured the second-generation of on-board diagnostics. Among many things, this standardized some of the programming and trouble coding in a vehicle's power train control module. Before 1996, vehicles used computers called electronic control modules. So, the process of checking a 2005 Chevrolet Silverado's PCM is the same as other contemporary vehicles. A bad PCM poses a serious problem. The module is responsible for checking for engine malfunction. If it doesn't work, you will not get advance warning of potentially serious problems.
Compile a list of OBD-II trouble codes that deal only with the Silverado's PCM. You can find such codes in your OBD-II scanner's handbook, as well as a Haynes Repair Manual for the 2005 Silverado. If you do not own a manual, you can find the codes online for free. The codes you're searching for mention "PCM" in their definitions. For example, P0606 means "PCM Processor Fault."
Get behind the Silverado's wheel. Place your research material on top of the dash. Then, look under the dash for the OBD-II system's computer port. You will find this data link connector next to the left kick panel. It will be uncovered, and it will be in the same location for 1500, 2500 and 3500 versions of the 2005 Silverado.
Connect your OBD-II scanner to the Silverado's computer outlet. Switch the device on, and then turn on the Silverado's electronics. Depending on your brand of scanner, you man also need to crank the Silverado's engine.
Look at your OBD-II scanner's screen. Your device may have not been pre-programmed to automatically retrieve trouble codes. If so, enter in a "read" command. The exact way to do this is not the same in every brand of OBD-II device, so consult your scanner's handbook for the exact directions.
Look at the codes retrieved by your device. Consult the researched material you left on top of the dash, and look only for PCM-related trouble codes. If you do not see any of those codes on your scanner, then your Silverado's PCM is functional without problem. If you do find PCM-related codes, you should bring the Silverado to a Chevrolet approved mechanic. The PCM, in the best case scenario, may only need to be reprogrammed. In the worst case scenario, it may have to be replaced.
