Malfunction Indicator Lamp: Description and Operation

PURPOSE
The Malfunction Indicator Lamp (MIL) is intended to alert the driver of certain malfunctions in the Electronic Engine Control (EEC-IV) system.

During self test the MIL can also be used to display the service codes.

OPERATION
The message center is used to display the "CHECK ENGINE" and/or "CHECK DLC" messages.

The Powertrain Control Module (PCM) transmits the "CHECK ENGINE" message to the message center through the Data Link Connector (DLC).

The "CHECK ENGINE" message is activated when the PCM switches to an alternate strategy of operation. This process is called Failure Modes Effect Management (FMEM).

When the vehicle enters FMEM the "CHECK ENGINE" message will be displayed and accompanied by a one second tone every five seconds. The tone will be suppressed after one minute.

The "CHECK ENGINE" message will also be displayed during a period of Hardware Limited Operating Strategy (HLOS) operation.

In addition to the "CHECK ENGINE" message and tone, the message "CHECK DLC" will also be displayed.