wiring diagram for a 89 icv m40

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arrisbmw
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Wed Jun 12, 2019 2:07 pm

hi All,

has anyone got a wiring diagram for the idle speed control system please , or can they explain to us how it works. electrically
I,ve been trying to trace a fault on my 89 m40 . I understand it involves the tps and the blue sensor ,
i think its basically the same as the 6 pot which has 3 wire to it rather that 2 for the m40
there is one on here but its for pre face lift cars,


thanks
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Brianmoooore
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Sun Jun 16, 2019 10:47 pm

M40 ICV is essentially a DC electric motor fighting against a spring. The more voltage that is applied to the motor, the more it can turn the spring until it stalls.
The control system decreases or increases the voltage applied to the motor in an attempt to keep the frequency of the pulses from the crank position sensor the same as a reference frequency stored in the software. The reference frequency varies slightly in response to the signals from the blue temp. sensor and TPS.
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arrisbmw
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Mon Jun 17, 2019 11:01 pm

thanks for the reply Brian. for some reason I can't open the image.

is it a wiring diagram ?
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