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Unread 05-05-2012   #1 (permalink)
92Mustang5.0LX is offline Apprentice

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Default KOER Code 12? IAC?

trying to pass smog =( hate it so much. I did a KOEO got pass code 11, CONTINUOUS MEMORY got 31, KOER got code 12.

i know that the 31 has to do with the EGR sensor (correct?)
I googled code 12 even though the book said RPMS at idle are out of range/high. What does that have to do with? is it the IAC? Stupid google said it had to do with the airbags. i dont think so. Any help would be awesome. thank you

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Unread 05-05-2012   #2 (permalink)
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The book that came with my scanner lists code 12 as "System cannot raise engine speed above normal idle." As for what that really means - I would just be talkning out my butt. Best of luck!
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Unread 05-05-2012   #3 (permalink)
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Yea i think that means the same thing. just another way of saying it. The code 12 im pretty sure it has to do with the IAC. I just want someone to confirm it before i replace it.
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Unread 05-05-2012   #4 (permalink)
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Code 12 generally means the idle is to low. You should try cleaning out the throttle bodyand IAC valve and see if that helps first.

What is the idle rpm now?
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Unread 05-05-2012   #5 (permalink)
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Seems like 750 or 800. i have a picture of it idle at normal. I just bought a new EGR sensor. havent put it in yet. but that just takes care of 31. i still need 12.
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KOER Code 12? IAC?-normal-idle.jpg  
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Unread 05-06-2012   #6 (permalink)
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if you see in the picture my temp gauge doesn't work. Is that the temp gauge sending unit? I already replaced the instrument voltage regulator cause of the gas gauge.
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Unread 05-06-2012   #7 (permalink)
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I have an update. i took off and cleaned the IAC. Got as much crap out as i could. Then i cleaned the throttle body. i also replaced the EGR sensor which fixed code 31. put everything together. Waited for it to warm up tested it and still got code 12. Does that mean the IAC is bad? Thats the only code its giving. Is there anything else that can give a code 12 besides the IAC?
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Unread 05-06-2012   #8 (permalink)
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Raise the idle speed up a little and see if the code goes away. Looks like the IAC valve is shot though. Or not fully functioning.
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Unread 02-06-2013   #9 (permalink)
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Any update on the code 12 issue? I'm having the same problem.
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Unread 02-11-2013   #10 (permalink)
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Yup it was my IAC. I bought a new one at auto zone and it fixed the problem.
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Unread 02-11-2013   #11 (permalink)
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code 12 refers to engine control of idle speed during KOER self test if engine speed does not rise to about 1500 rpm during KOER self test then code 12 results.
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