Malfunction Indicator Lamp: Description and Operation

Self-Diagnosis System:

PURPOSE
Malfunction indicator light (MIL) informs the driver when a malfunction is detected in an ECU monitored device. Also used to read trouble codes stored in ECU memory.

LOCATION
On the instrument panel.

OPERATION
If the ECU detects a monitored device malfunction, the MIL will stay ON with the engine running and diagnosis connector TEN terminal not grounded. If the terminal is grounded, the MIL will flash malfunction codes corresponding to the defective input/output devices and/or their circuits. If more than one failure is present, the lowest number code is displayed first, followed by remaining codes in numerical order.