Engine management system - EDC (Cruise Control): Description and operation

When a new immobilisation ECU is fitted to a vehicle during service, the new immobilisation ECU must be supplied with a seed that matches the vehicle. This information is held by Rover. The rolling codes in the new immobilisation ECU and the existing ECM must then be synchronised using TestBook.

The immobilisation ECU receives engine speed information from the ECM to inhibit starter motor operation when the engine is running, to prevent damage to the starter drive pinion and ring-gear. Engine speed information is broadcast on the CAN bus by the ECM. The instrument pack converts and broadcasts the engine speed signal on the K bus where it is received by the immobilisation ECU.

Cruise Control

The ECM incorporates a cruise control program which is activated and deactivated by an input from the cruise control interface ECU. ENGINE MANAGEMENT SYSTEM - EDC, DESCRIPTION AND OPERATION, Description.

During cruise control operation, the ECM controls vehicle speed by adjusting fuel injection duration and timing. On automatic gearbox models, when the accelerator pedal is released during cruise control the ECM outputs a calculated 'throttle' angle signal to the EAT ECU in place of the actual 'throttle' angle signal derived from the Throttle Position sensor. The calculated 'throttle' angle is derived from fuel demand.