Malfunction Indicator Lamp (MIL) (Engine management system - EDC)

Malfunction Indicator Lamp (MIL)

The ECM has a built in self-diagnosis function. If certain faults are detected, the MIL in the instrument panel will illuminate, and the ECM will implement a back-up facility to enable the system to continue functioning, though at a reduced level of performance.

Minor faults will not illuminate the MIL, but will be stored in the ECM’s memory and can be retrieved at a later date using TestBook. If a serious fault is detected, the warning light will illuminate and the engine management system will shut down, preventing the vehicle 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 remain stored in the ECM’s memory.

Cooling fans (all models)

On all models, two electric cooling fans are fitted in a housing behind the radiator.

The ECM controls the operation of the cooling fans. The ECT sensor constantly sends signals to the ECM. When engine coolant reaches a temperature of 106°C, the ECM switches the cooling fans on, in slow mode. When the engine coolant reaches a temperature of 112°C, the ECM switches the cooling fans from slow to fast mode. When the engine coolant temperature is reduced to 106°C, the ECM switches the cooling fans to operate in slow mode until the temperature is reduced to below 100°C, when the ECM switches the fans off. When the ignition is turned off, the fans stop.

Cooling fans (Vehicles with air conditioning (A/C) only)

The ECM controls the A/C grant output. If an input is received from the A/C system the ECM will consider engaging the A/C clutch. The ECM considers the coolant temperature and the throttle position before the A/C grant is operated. When the A/C grant is started, the cooling fans turn on in slow mode, unless the coolant temperature is above 112°C when they operate in fast mode.

The ECM provides two outputs to control the two cooling fans; slow mode and fast mode. The modes of operation vary depending on signals received from the A/C thermostat, the ECT sensor and the ECM. In slow mode, both fans operate in series sharing the same electrical feed. In fast mode, both fans operate in parallel, each fan receiving its feed from a separate source. When the ignition is turned off, both fans stop.

If an engine temperature of 117°C is sensed by the ECT sensor, the ECM can override the A/C request to reduce load on the engine. The air conditioning request is reinstated when the coolant temperature reaches a 115°C.

Hill descent control signal (Vehicles with ABS only)

See BRAKES, Information.

The ECM constantly provides signal information of throttle position and engine speed and also assesses other engine inputs to produce an engine torque signal. These signals, together with engine and gearbox identifiers, are passed to the ABS ECU to control hill descent.