Mil Light ("Check Engine"/"Service Engine Soon") Operation: Introduction

The light alerts the driver of certain malfunctions in the EEC-IV system. If the light is on during vehicle operation, the vehicle should be serviced and inspected as soon as possible. It is not necessary to immediately turn off the vehicle or have it towed to a service facility.

The light will come on while the engine is operating in Failure Mode Effects Management (FMEM) or Hardware Limited Operation Strategy (HLOS) modes. The light will stay on as long as the fault causing it is present. If the fault is no longer present, the light will turn off.

If the light comes on and then goes off while in operation, the code that caused the light to illuminate will be stored in ECA memory as a Continuous Memory code.

The light may also be used to retrieve all service codes. When hooked-up for KOEO or Engine Running self-test, the light will retrieve all codes, not just Continuous Memory codes which turn the light on during vehicle operation.