POSSIBLE IAC VALVE REPLACEMENT?

  • Tiny
  • tex
  • 2001 Hyundai Elantra
  • 120,000 miles

Engine revving high. When I disconnect the IAC valve, engine stops idling high but it is still rough. When I put the IAC back, it revs up high again. Already checked for vacuum leaks and didn't find any. It wasn't sticking, but I cleaned it anyways. I had 1 TPS code - P0121. I also checked the value and everything is in spec on TPS. Checked throttle.
How do I bench test the IAC valve? Could this be the problem? How would I check the values between the terminals on the IAC?

Friday, June 22nd, 2012 AT 2:02 AM

7 Answers

  • Tiny
  • saturntech9
  • Expert
  • 28,244 posts

So when you cleaned the iac did you remove it?Also does the tps code come right back when you clear it?

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Friday, June 22nd, 2012 AT 6:01 AM
  • Tiny
  • tex
  • Member

I did the bench test on tps. All the values are in spec. Didn't clear the code as yet.

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Friday, June 22nd, 2012 AT 10:56 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,244 posts

Please clear the code and see if it comes right back?

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Saturday, June 23rd, 2012 AT 3:32 AM
  • Tiny
  • tex
  • Member

Code came back. So I got a hold of a new IAC and checked the values with mine. The values are the same, which leads me to believe that the IAC is ok. I now feel that it may be the map sensor. How would I go about checking that? Thanks.

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Saturday, June 23rd, 2012 AT 4:42 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,244 posts

We need to find out why it keeps setting the tps code thats where I would start. Follow the directions I posted and let me know what you find.

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Sunday, June 24th, 2012 AT 3:57 AM
  • Tiny
  • tex
  • Member

Thanks for your help. So it turned out to be an intermittent vacuum leak between the 3rd and 4th cylinder gasket. The gasket was broken and stuck. Map sensor needed replacing too because it had a high value resistance between the map sensor terminals (15 k-ohms) when a new one only had 3.0 ohms. Because of the faulty MAP sensor, I couldn't check for the vacuum leak properly. So I hope this helps anyone out there who may have same the problem I had. My care is working GREAT now, even better than before. Thanks again.

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Monday, June 25th, 2012 AT 8:58 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,244 posts

Your welcome glad to hear you got it fixed.

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Monday, June 25th, 2012 AT 9:02 PM

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