XC70 AWD L6-3.2L VIN 98 B6324S (2009)
Engine Control Module: Description and Operation
The engine control module (ECM) controls, amongst others, the following functions:
Evaporative emission system (EVAP) valve
engine cooling fan (FC)
air conditioning (A/C) compressor.
variable intake system
variable camshaft profile.
The engine control module (ECM) is supplied with battery voltage (Ubat) via fuses in the central electronic module (CEM) and in the integrated
relay/fusebox in the engine compartment.
To prevent certain stored date from being erased from the engine control module (ECM) when the ignition is switched off, the control module also has a
30-supply. This supply is from the integrated relay/fusebox in the engine compartment.
The control module is grounded via the wiring which is connected at the right-hand suspension turret.
The engine control module (ECM) contains a voltage regulator which maintains a low voltage (5 V) in internal components in the control module such
Functions which require battery power (Ubat) and high output are controlled by external or internal power stages. For example ignition coils have
external power stages (integrated into the ignition coils) while the power stages for the injectors are integrated in the engine control module (ECM).
The micro-processor in the engine control module (ECM) receives signals from the different sensors and control modules in the vehicle. The
micro-processor uses a program which interprets the signals from the different sensors and how the components and functions should be controlled.
The engine control module (ECM) has several self-learning (adaptive) functions. It continually adapts ongoing calculations to changing circumstances
(such as wear, air leaks, differences between different fuels).
Emissions are kept low through efficient management of the injection period, ignition, evaporative emission system (EVAP) valve and camshafts etc.
Faults which affect emissions can be detected by running diagnostics for functions and components.
The engine control module (ECM) is located in the cold zone in front of the windshield.
The engine control module (ECM) communicates with other control modules using controller area network (CAN) communication or LIN
The engine control module (ECM) checks activations, input and output signals and functions using an integrated diagnostic system. A diagnostic trouble
code (DTC) is stored if, after validation, the control module detects a fault. In certain cases the faulty signal is also replaced with a substitute value or
certain functions are limited.
For example, substitute values can be set for:
engine coolant temperature (ECT) sensor
mass air flow (MAF) sensor
throttle position (TP) sensor