My car is sick

[shane@mbtech]

Originally Posted by _Nathan_

The throttle pedal has 2 outputs which describe throttle pedal position, one goes from 0% high volts to 100% low volts, and the other from 0% low volts to 100% being high volts, the sensor on the motor and the throttle rail itself perform the task of current position feedback and again one goes high to low and the other goes low to high. The sensor on the flap doesn't perform a function of either position demand or current position feedback in the closed loop DBW system, simply tells the ECU the position of the flap.

At all times both demand signals (pedal) should read within a few percent of each other, and likewise both feedback signals should read within a few percent of each other, the ECU drives the motor using PWM based on the aim error (difference between desired position - calculated in ECU based on lots of inputs including throttle position - and the feedback position). If either the position demand or feedback position fail their checks (the sensors for that part deviate from each other by too much) then limp home or similar should activated, there is no way a throttle should get pinned open by a failed sensor, think of the law suits and all the stories that would be all over the web of e46s suddenly going WOT on track and killing people.

Also if I may be so bold, how can a car be in gear and rev without accelerating unless a driveline component has failed meaning no drive, and why would putting it in neutral stop it revving if the ECU was driving the motor to WOT, unless the poster meant he was stationary and the lower 6k ish rev limiter kicked in when it was moved to neutral?

Need more info...

Exactly what I was thinking but I was taking a dump today when I read it, so I couldnt be arsed typing all that on the fricking I phone