9-3 Convertible (9400) L4-2.0L Turbo (2.0 HOT) (2003)
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There are two throttle position sensors connected to the throttle spindle. The sensors are two potentiometers powered with 5 V from control module pins
46 and 69, which are coupled together in the throttle body, and grounded from control module pins 22 and 70, which are also coupled together in the
throttle body.
The voltage from sensor 1 is connected to control module pin 33 and increases with the throttle position. The voltage from sensor 2 is connected to
control module pin 10 and decreases with the throttle position. The sum of the two sensor voltages is always 5 V.
The voltage from sensor 1 is used by the control module as a value for the current throttle position.
Air mass control requests a certain air mass/combustion. Throttle control converts this value to a requested value for throttle position sensor 1 and
compares it with the current value for the sensor.
The difference gives rise to a throttle motor PWM with a polarity that rotates the throttle until the current value corresponds with the requested.
If a major fault should occur in the throttle control, the control module will ground pin 36 and the limp-home solenoid will operate. The solenoid, which
is located on the throttle body, then connects the pedal cable to the throttle spindle. The throttle motor is de-energized and the throttle is then controlled
directly from the accelerator pedal.
