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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.