Engine Management System - From 99MY
The V8 engine for models from 99MY is controlled by a Bosch Motronic 5.2.1 engine management system. The ECM uses sensors to determine ambient conditions and operating data and uses this data and the information stored in an internal memory map to control the electronic ignition and fuel injection. The system features:
- Idle speed control (ISC)
- Adherence to regulatory emissions standards
- Adherence to OBDII legislation for NAS vehicles
- Security immobilization
- Fuelling quantity
- Exhaust emission control using HO2S sensors and closed loop fuelling
- Knock control
- Ignition timing
- Interfaces with other electronic systems including Electronic Automatic Transmission (EAT) ECU, Transfer Box ECU, ABS ECU, BeCM and instrument pack.
The engine management system controls the engine fuelling by providing full sequential injection to all cylinders. Ignition is controlled by a direct ignition system which is provided by four double ended ignition coils operating on the wasted spark principle.
Sensors used in the engine management system include:
- Mass air flow sensor - to determine the mass of air entering the engine
- Throttle position sensor - to detect the current throttle angle
- Coolant temperature sensor - to detect current engine coolant temperature
- Exhaust gas sensors (HO2S) sensors - to determine the exhaust emission level.
The ECM software program processes these signals and determines what actions to implement based on these signals and the internal mapped data settings.
The on-board diagnostic system detects any faults which may occur within the EMS. The system monitors and reports on any ignition, fuelling or exhaust faults which cause an excessive increase in emissions. Fault diagnosis includes failure of any EMS sensors and actuators, as well as misfire, catalyst damage, catalyst efficiency, fuel evaporative loss control and exhaust leaks.
The system incorporates certain default strategies to enable the vehicle to be driven in case of sensor failure. This may mean that a fault is not detected by the driver. The fault is indicated by illumination of the malfunction indicator lamp (MIL) on North American specification vehicles.
The ECM also communicates with the EAT ECU using a CAN data link for the transmission of OBD information.
A further feature of the system is 'robust immobilization', (fitted to vehicles in most markets). Upon arming the alarm, the EMS ECM disables the injectors and the Body electrical Control Module (BeCM) inhibits the crank relay (the vehicle cannot be started until the alarm is disarmed).
CAUTION: System sensor connectors can be contaminated by oil or coolant when disconnected during repair or testing. Use a suitable cap to prevent dirt or fluid ingress.