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Engine speed

Engine speed


Information on current engine speed is obtained via pin 6 of the TCS control module from pin 43 of the MOTRONIC control module.

Information on engine speed is necessary to enable:


the control module, together with information on the positions of the main throttle butterfly and the TCS throtlte butterfly, to calculate engine torque

the control module, together with speed signals from the wheels, to calculate the appropriate gear.

The signal is a square wave measuring about 40 Hz at idling speed and about 125 Hz at 2500 rpm. In the event of an incorrect signal or if there is no continuity or a short in the circuit, then diagnostic trouble codes are generated, the TCS OFF lamp lights up and the system is rendered inoperative.