System Overview

System Overview

The Engine Control Module (ECM) controls activation's, in- and output signals together with functions built-in diagnostics. When the control module detects a fault then a fault code will be set after validation. In certain cases will the faulty signal be replaced with a substitute value or certain functions will get restricted functionality. Substitute value can be set, for instance in:
- Engine temperature sensor
- Air mass meter
- Throttle position sensor
- Air pressure
- Fuel pressure

Substitute values are calculated by means of signals from other components and mathematical calculations. Other substitute values are fixed and pre-defined values in the control module.

The substitute values will enable the vehicle with limited emission exceedance to be driven, despite vital functions/components are faulty. Functions which be limited can be, e.g.:
- Turbo regulating
- Camshaft regulating (CVVT)
- Lambda regulating
- Throttle angle

Substitute values and reduced functionality exist in order to keep the system operating, protect components or for safety reasons (for instance the electronic throttle). Any fault codes will be accumulated in the memory of the ECM. The information can be read by means of VIDA (Vehicle Information and Diagnostics for Aftersales) or a Scantool via the diagnostic Connector (DLC) in the vehicle.