9-3 Viggen Coupe (9400) L4-2.3L Turbo (B235) HO (1999)
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Crankshaft Position Sensor: Description and Operation
Trionic T5
The control module receives information concerning the position and speed of the crankshaft on pin 41 from the crankshaft position sensor.
There is a slotted ring with 58 ribs mounted on the crankshaft. The sensor is inductive and mounted on the wall of the crankcase.
The distance between the sensor and the slotted ring is between 0.4-1.3 mm and is not adjustable.
The sensor acts like a generator and delivers a sinusoidal alternating current. By measuring the frequency, the control module will be able to determine
the engine speed. There are two ribs missing after the 58th one. When rib 1 subsequently passes the sensor, the control module will know that the
crankshaft is 117 before top dead centre (BTDC).
The voltage from the crankshaft position sensor varies with the speed. At idling speed, the voltage will be 7-10 V (AC) and at 2500 rpm approx. 15-20
V (AC). However, it is the frequency and not the voltage that is of interest to the control module.
The control module uses mainly engine speed and crankshaft position to calculate the ignition timing, injection timing, injection duration, boost pressure
and idle speed control.
Fuel injection is terminated when the engine speed exceeds 6400 rpm. 6200 rpm applies on cars with automatic transmission.
