System Diagnosis: Operation
WARNING: This page is about a different car, the 2007 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The PCM can test many of its own input and output circuits. If the PCM senses a fault in a major system, the PCM stores a Diagnostic Trouble Code (DTC) in memory.
For DTC information see On-Board Diagnostics. Refer to DESCRIPTION .