9-3 Arc/Aero (9440) L4-2.0L Turbo (2.0 T) (2004)
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Limp Home Throttle Valve: Description and Operation
Throttle control
1. Throttle motor
2. Throttle disc
3. Connector
The throttle disc is turned by a DC motor via a reduction gear. The motor is supplied from ECM with a PWM signal from pins 46(B), 63(B) and 47(B),
64(B). ECM can turn the throttle disc in both directions, i.e. open and close. A spring strives to keep the throttle slightly open.
When the throttle control goes into limp-home mode then it is this position that determines the throttle area and thereby controls the air mass/combustion
that can enter the engine. Fuel shut-off and ignition timing are used as control instruments in order to control the engine torque. The idling speed is
around 900 rpm. The engine will run erratically with low loads due to fuel shut-off. The car can still be driven but performance will be impaired.
Two throttle position sensors are connected to the shaft. The sensors comprise potentiometers supplied with 5V from ECM pins 30(B) and 31(B) and are
grounded to ECM pins 34(B) and 35(B).
