Saab 9000 - Page 37

34 Technical Description
Throttle position sensor
42
45
The position sensor consists of a potentiometer con-
nected to the throttle spindle.
The sensor is supplied with 5 V from ECM pin 42 and
is grounded from ECM pin 67. The voltage from the
sensor is connected to ECM pin 45 and is proportion-
al to the accelerator setting.
The voltage is approx. 0.5 V during idling and approx.
4.5 Vat wide open throttle. The ECM uses the volt-
age from the sensor to identify idling, partly open
throttle and wide open throttle. During idling the ECM
uses a special ignition control matrix and adjusts the
idling speed.
The closed loop is disconnected at wide open
throttle.
Fuel injection is
shut
off
at wide open throttle in con-
junction with starter motor cranking.
A richer mixture is supplied during a.cceleration and
a leaner mixture during deceleration.
Maximum boost pressure is also dependent on the
position of the throttle. In the event of sensor
failure
or a break in the circuit, the engine control module will
set wide open throttle as the default value.
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