Check Engine Light & Malfunction Indicator Light (Mil): Notes

CHECK ENGINE light and MIL are intended to alert driver of certain malfunctions in EEC-IV system.

Light may also be used to retrieve service codes stored in ECA. When hooked up for KOEO SELF-TEST or KOER SELF-TEST, light will display all codes which turn on light during vehicle operation, not just Continuous Memory Codes.

If light comes on during vehicle operation, vehicle should be inspected as soon as possible. Immediately turning off engine is not necessary; vehicle can be driven with light on.

If light comes on and then goes off during vehicle operation, code causing light to glow will be stored in ECA memory as a Continuous Memory Code.

Light should come on when ignition is turned on and go out when engine is started. If light does not come on, see SYMPTOMS in TESTS W/O CODES article in the ENGINE PERFORMANCE Section. If hard fault codes are not present, ECA turns out light when it receives a Profile Ignition Pick-Up (PIP) signal.