Malfunction Indicator Lamp: Description

The OBD system interfaces with the driver via the MIL, which is located in the instrument pack. A bulb check takes place every time the ignition is switched to ignition position II and until the engine is cranked.

The ECM monitors the driver junction temperature to detect an electrical fault. See Fig 1 . A fault is detected if the following condition is satisfied:

1. MIL driver short circuit to battery positive, i.e. the driver stage junction temperature exceeds a temperature threshold.

Fig 1: Malfunction Indicator Lamp DTC Testing

Courtesy of LAND ROVER NORTH AMERICA, INC.