XC90 AWD V8-4.4L VIN 85 B8444S (2005)
The function of the starter motor relay is to supply power to the starter motor. See also: Function, B8444S See: Powertrain Management/Computers and
Control Systems/Description and Operation/Engine Control Module (ECM)/Function
The starter motor relay is in the relay/fuse box in the engine compartment.
Engine cooling fan (FC)/Engine cooling fan (FC) control module
Note! The engine cooling fan may have a post-run of up to approx. 6 minutes after the engine has been turned off. The time for the fan's
post-run depends on engine temperature, temperature in the engine compartment and pressure level in the AC-system.
Warning! Be careful since the engine cooling fan may have a post-run after the engine has been turned off.
The engine cooling fan (FC) cools the coolant, engine compartment and the condenser when the air conditioning (A/C) compressor is running.
The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control module. The control module
then activates the fan at different speeds. The speed of the engine cooling fan (FC) is determined by the engine control module (ECM), depending on the
coolant temperature (based on the signal from the engine coolant temperature (ECT) sensor) and the vehicle speed.
The temperature conditions for engagement of the different engine cooling fan (FC) stages may vary slightly, depending on the engine variant and the
equipment level. The temperature conditions apply when:
the A/C is off
no faults are detected by the Engine Control Module (ECM).
There is an internal diagnostic function in the engine cooling fan (FC). This function transmits a signal to the engine control module (ECM) if the fan is
partially or fully blocked. To do this, the engine cooling fan (FC) control module grounds the pulse width modulation (PWM) signal based on a
The engine cooling fan (FC) and its control module are behind the radiator.
The engine cooling fan (FC) can be diagnosed by the engine control module (ECM) and can be activated.