Volvo Workshop Manuals
XC90 AWD V8-4.4L VIN 85 B8444S (2005)
Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Description and Operation > System Overview > Page 1782
Engine Control Module: Description and Operation
The starter motor (6/25) is supplied with power via the starter motor relay (2/35), the starter motor relay is controlled by the engine control module
The start process is as follows:
1. The ignition key is turned to start position (position III)
The engine control module (ECM) interprets this high signal as a request to activate the starter motor.
3. The engine control module (ECM) activates the starter motor solenoid by grounding and powering the coil for the starter motor relay.
5. The engine control module (ECM) activates the starter motor until the engine starts (the engine speed (rpm) exceeds a certain value)
If the ignition key returns to ignition position (position II) before the engine is started, the starter motor continues to run. The starter motor runs until the
0° C or higher, approximately 3 seconds
less than 0° C, up to approximately 5 seconds.
If the engine does not turn or if the engine speed is extremely low when the start relay is activated, the engine control module (ECM) interrupts start
Activation of the starter motor is not permitted or is interrupted if:
the engine is running (the engine speed (RPM) above a certain value)
the immobilizer function does not allow a start. For further information also see Design and Function, Immobilizer
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