System Diagnostics: Notes

NOTE: Malfunction Indicator Light (MIL) may also be referred to as CHECK ENGINE Light.

Self-diagnostic capabilities of this system, if properly used, can simplify testing. Powertrain Control Module (PCM) monitors several different engine control system circuits.

If a problem is sensed with a monitored circuit, PCM memory stores a fault, MIL glows and PCM enters limp-in mode. In limp-in mode, PCM compensates for component failure by substituting information from other sources. This allows vehicle operation until repairs can be made.

Test circuits and repair or replace components as required. If problem is repaired or ceases to exist, PCM cancels fault after 50 ignition on/off cycles.

A specific fault results from a particular system failure. A fault does not condemn a specific component; component is not necessarily reason for failure. Faults only suggest probable malfunction area.