OBD System Functions

Diagnostic Trouble Code (DTC) Table:

SELF-DIAGNOSTICS
The Engine Control Module (ECM) monitors several circuits and components to determine if they are functioning properly. If a malfunction is detected in certain circuits the (CHECK ENGINE) Malfunction Indicator Lamp (MIL) will be illuminated to alert the driver that a problem is occuring. The lamp will remain illuminated as long the fault is present. The ECM will store a code in its memory to aid the technician in diagnosis. If the lamp turns off, the fault is no longer present, but the code will be stored for 50 attempted engine starts or until the code is cleared from the memory. This aids in diagnosing intermittant problems.