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Crankshaft position sensor

Crankshaft position sensor





The engine control module receives information from the crankshaft position sensor regarding engine speed and when the engine is at top dead centre. This information is used to calculated permissible injection quantity and when pressure build-up of the fuel should start.

In one of the crankshaft counterweights, there are four air gaps. When the air gaps pass the sensor, AC voltage is induced whose frequency is proportional to the engine speed. Two of the four air gaps are used by the control module to mark top dead centre. These air gaps are displaced 13° in relation to top dead centre.

Note that the special tool to block the engine at top dead centre does not fit in the crankshaft position sensor air gap. There is instead a special socket for the special tool. This socket is not displaced in relation to top dead centre.



Diagnostics

If the following diagnostics run, it could be an indication that the crankshaft position sensor is not working:


• P0335, Tachometer sensor, No Signal While Engine Running

• P0336 Tachometer sensor crankshaft, feasibility fault with pump camshaft sensor.

• P0337 Tachometer sensor, No Signal During Start Procedure.


Pump speed x 2 is used as a substitute value for the crankshaft position sensor.