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It errrrr resets the stepper motor (back to its default closed position). If the stepper motor gets stuck, confused or someone else moves it other than the ECU then the ECU can lose track of where the stepper motor is. (it only assumes where it is from the number of signal pulses it gives it). Resetting it puts the stepper motor back exactly where it should be so the ECU knows where it is.

Symptoms of it being in the wrong place are high or low speed idling or an erractic idle. Also poor on off throttle response can also be observed.

do a forum search and you'll find out how to do it. It only takes 10 seconds so it is worth a try.
 

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Discussion Starter · #3 ·
ok thanks mate,i have noticed that when u rev the car the revs dont seem to fall straight away.ill give it a go:)
 

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jay27 said:
ok thanks mate,i have noticed that when u rev the car the revs dont seem to fall straight away.ill give it a go:)
Sounds like a sticky throttle body or something in that general area, so the stepper motor is a good place to start.
 

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If your car has a plastic throttle body these are known to stick - soemthing worth checking. Replacement with a metal one is the best cure.
 

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Discussion Starter · #6 ·
b4 i brought the car it was sat for a few weeks with a flat battery.will it do any harm if i reset the stepper motor and what the worse that can happen?

do i press the accelerator pedal to the floor or just a little bit?
 

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The worse that can ahppen is the idle will go a bit loopy for a few minutes whilst the ECU works out where it is.

Switch the igntion on
Depress throttle pedal fully 5 times in quick sucession. You'll hear the stepper motor whir a bit. Then when it stops start the car and wait for the idle speed to settle down.

Job done
 

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E_T_V said:
It errrrr resets the stepper motor (back to its default closed position).
As far as I'm aware resetting the stepper with the throttle pedal doesn't set it to it's default position. It simply clears the learned position.
The position that the stepper settles to is it's learned position. I.E. the position at where the ECU regards the idle as normal.
 

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That procedure does not reset the stepper motor, the only way of re-referencing the stepper motors position is through a T4.
 

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jay27 said:
nothing happened,no noise nothing lol
You won't get a noise, but you may notice that your car turns over a few more times than normal when it starts the first time and the revs will hunt for few seconds and then settle.
 
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