Control Module
The Motronic 4.4 is an electronic engine management system which controls:
- fuel injection
- ignition
- idling speed:
- turbocharger (TC) boost pressure
- engine cooling fan (FC)
- EVAP system
- air conditioning (A/C) system
- pulsed secondary air injection system (PAIR).
The engine control module (ECM) incorporates a micro-processor which receives signals from the various sensors in the car. This micro-processor uses a program to compute the necessary engine management functions.
The engine control module (ECM) incorporates adaptive functions, which enable it to adjust its computations continuously to suit running conditions.
By managing the engine effectively exhaust gas emissions can be kept low. CO content and idling speed do not need to be adjusted. The need for servicing is small.
The engine control module (ECM) also has an on-board diagnostics system. Signals from sensors, and the operation of the three-way catalytic converter (TWC) and EVAP system are continuously monitored. If possible the engine control module (ECM) will adopt fixed substitute values (limp-home values) to enable the car to be driven if certain signals are faulty or missing.
Substitute values can be adopted for:
- engine coolant temperature (ECT) sensor
- throttle position (TP) sensor
- Heated oxygen sensors (HO2S)
- mass air flow (MAF) sensor
Faults are recorded in the engine control module (ECM) memory. Information can be read-off using the Volvo Scan Tool (ST) connected to the data link connector (DLC) in front of the gear shift and under the coin tray on the center console.
The engine control module (ECM) is housed in a ventilated box in the engine compartment.