Engine management system - EDC (Diagnostic connector): Description and operation

Diagnostic connector

The diagnostic connector is located on a bracket behind the centre console and allows engine tuning or fault diagnosis via TestBook to be carried out without disturbing the system electrical connections. It utilises the ability of the engine control module to store certain faults.

Malfunction indicator lamp

The engine control module has a built in self-diagnosis function. If a fault is detected the malfunction indicator lamp (MIL) in the instrument pack will illuminate, and the control module will implement a back-up facility to enable the system to continue functioning, though at a reduced level of performance. If a serious fault is detected the warning light will illuminate and the engine management system will shut down preventing the car from being started or driven.

The MIL will remain illuminated until the starter switch is turned off. If the fault is still present when the starter switch is turned back on the MIL will illuminate. If the fault is not present when the starter switch is turned on, the MIL will remain extinguished, but a fault code will be stored in the memory of the engine control module.