P0171 Troubleshooting
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This is a discussion on P0171 Troubleshooting within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I know this code has been discussed many times, and I've even looked through troubleshooting guides, but before I spend ...

  1. #1
    Registered User Uh Oh's Avatar
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    P0171 Troubleshooting

    I know this code has been discussed many times, and I've even looked through troubleshooting guides, but before I spend any more money I just want to get a couple specific answers.

    I got this code once before, and jiggling the MAF sensor connection fixed it, so I was almost certain it was faulty when that didn't work a second time. Of course, I tried cleaning it first to no avail. Replacing it wasn't the problem either. The next step I took was to check my front o2 sensor. It was loose. I decided to unscrew it all the way and twist it the reverse way so it's wire would untwist itself as I screwed it back in, but I found the threads were seized and was unable to get it back in.

    Now I'm looking at $200 for a new one from autozone, which seems a little high for me. Maybe they forgot to mention a core fee? What are my chances this was my problem? After being out $130 for the MAF, and $150ish (If there was in fact a core fee attached) if I still have a CEL after tomorrow, I might damn near shoot myself.
    -Holden
    Bugeye wagon - ERZ Uppipe - TurboXS Axleback - Swift Springs - JNA Lip

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  3. #2
    Moderator Donkey's Avatar
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    What mods? You can get the sensor cheaper on line.
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  4. #3
    Registered User Uh Oh's Avatar
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    As far as the engine goes, just a silencer delete, uppipe, and axleback.

    Since the 02 sensor is now completely out, I'm afraid to drive it while waiting on a part to be delivered. Although it does sound pretty bad ass. :P

    I guess I'll just suck it up and spend the $200. I think the loose o2 sensor might have also been causing some turbo lag, so even if it doesn't fix the CEL, at least it'll have fixed something.
    -Holden
    Bugeye wagon - ERZ Uppipe - TurboXS Axleback - Swift Springs - JNA Lip

  5. #4
    Moderator Donkey's Avatar
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    If it doesn't fix it then you probably have a vacuum leak or a post MAF/pre turbo inlet leak
    Resident Adviser @ WTF Tuning, LLC
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  6. #5
    Registered User Uh Oh's Avatar
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    Well, the o2 sensor was in fact the culprit. My car also seems to have more pick up now, so it must've been loose enough to create a pre-turbo exhaust leak before it got fouled. Strange that it never smelled off.

    Thanks for your help, Donkey.
    -Holden
    Bugeye wagon - ERZ Uppipe - TurboXS Axleback - Swift Springs - JNA Lip

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