Engine Control Module (ECM)

Fig 1: Engine Control Module

Courtesy of VOLVO CARS CORPORATION

The engine control module (ECM) (4/46) controls the ignition system in the vehicle and controls activation of the starter motor via the starter motor relay (applicable to B8444S only). The engine control module (ECM) also grants permission to the central electronic module (CEM), indicating whether the fuel pump is permitted to run when ignition is attempted. These functions are activated once an approved check of the ignition key has been carried out and an identity check has been carried out between the engine control module (ECM) and the central electronic module (CEM) and the result approved.

In order for the engine control module (ECM) to work in the immobilizer system, the control module must be programmed with codes. This takes place for the first time during assembly in the factory, and subsequently takes place in the event the control module is replaced (when downloading software).