Comprehensive Component Monitor

PURPOSE
The Comprehensive Component Monitor is a self-test strategy within the Powertrain Control Module (PCM) that detects malfunctions of any electronic powertrain component/system that provides input to the PCM and is not exclusively an input to any another On-Board Diagnostics II (OBD II) monitor.

OPERATION
Input components are considered malfunctioning by the Comprehensive Component Monitor if there is lack of continuity, or if the input signal is out of range or not in proper relationship to signals it is compared against (this is called a rationality check).


Output components are considered malfunctioning by the Comprehensive Component Monitor if there is lack of continuity or if an expected output response to a PCM command does not occur.


Malfunction Indicator Lamp (MIL) and Diagnostic Trouble Codes (DTC's)
After a malfunction has been present for two drive cycles, the DTC is stored in PCM memory and the MIL is turned on. Once the DTC has been stored in memory, the MIL will stay on as long as the malfunction exists. The MIL is turned off after three consecutive trips without the same malfunction being detected providing there are no other fault codes stored that would independently illuminate the MIL. The DTC will be erased from memory after 40 warm-up cycles without the malfunction being detected after the MIL is turned off. Another method of erasing the DTC is initiating a PCM Reset.