HOW TO REPLACE IAC MOTOR

  • Tiny
  • mezl
  • 1998 Mitsubishi Mirage
  • 100,000 miles

I have P0505 code problem and decide to replace a new IAC motor on 1998 Mitsubishi Mirage LS 1.8L 2Door.
I ordered a new IAC(parts# AC330) and want to replace it myself.
I know the IAC is blow the throttle but not sure how to remove it.
My question is about how to remove / install new IAC and which parts should be removed before IAC? What kind of adjustment is needed after replace a new ICA on Mirage?

Thanks

Wednesday, April 18th, 2012 AT 9:26 AM

5 Answers

  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

Disconnect and remove air hose.
Unplug the IAC wireharness.
Disconnect throttle cable.
Remove throttle body and coolant hoses.
Remove the holding screw for the IAC.
Clean the throttle body if it is dirty and clogged.
Reinstall new IAC.
Reinstall throttle body and coolant hoses, replace gasket if necessary.
Reverse above procedure.
Top up coolant and do not rreplace radiator cap yet.
Run ehgine for a few minutes and top up coolant if necessary.

The only thing you need to monitor would be the idling speed as cleaning the throttle body can affect the idle.

Adjustment is by the idle adjust screw on the throttle body.

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Wednesday, April 18th, 2012 AT 1:43 PM
  • Tiny
  • mezl
  • Member

I did replaced a brand new IAC by myself, but the error code P0505(IAC System Malfunction) still show up after I reset ECU couple times from OBDII.
What else could be wrong? I didn't adjust the idle speed because I don't know what's normal speed is. My car current rpm in neutral gear is about 1600rpm and 900rpm when I switch to "D". Does that normal? What else should I check in order to fix this P0505 problem? Thanks

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Wednesday, May 2nd, 2012 AT 3:48 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

The idling speed is not normal and either you have a faulty IAC or with its wiring.

Check the wiring for loose connections or broken wires.

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Wednesday, May 2nd, 2012 AT 3:09 PM
  • Tiny
  • mezl
  • Member

So, what is normal idling speed? Should I adjust idle speed screw for it? Thanks

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Wednesday, May 2nd, 2012 AT 5:59 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

The idling speed after engine has warmed up should be 750 to 850 rpm.

Always adjust the idling only after engine is at operating temperature.

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Wednesday, May 2nd, 2012 AT 8:11 PM

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