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Resident Guinea Wop
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Discussion Starter #1
Started my truck (2002 Sierra, LQ4) this morning and the MIL stayed lit.

I checked the code with my laptop/elm based scanner and it came up -

P0135, Heated O2 sensor heater circuit malfunction on bank 1 sensor 1

I cleared the code as I was driving along, MIL went out... No pending codes. Restarted twice, no light, no codes...

Is this only because my truck is warm? Think I will get the code again when I leave for lunch today?

Also, anyone have the GM P/N for that sensor?
 

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My Dixie Wrecked
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Take it to the mechanic that fixed mine. He'll straighten it out for ya! :LOL:
 

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After you clear it out it will take 50-100 miles of driving to re-learn it. so it might not come on for a couple of days or it might come on right away.
 

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Resident Guinea Wop
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Discussion Starter #5
Relearn what? An O2 sensor fault is detected on "POST" :crazy:

During testing, the HO2S heaters are checked for opens/shorts and excessive current draw. The code will set when current draw exceeds a maximum calibrated limit or falls below a minimum calibrated limit and/or an open or short is detected.

I just restarted it, no pending codes, no light... Thinking it could be a glitch, or just the sensor is on its way out... :think:
 

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HMM Power On Self Test huh! Well how bout that!
 

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It will illuminate the MIL after 2 consecutive faults. If it can go through 3 more starts without a fault, it will turn off. The history will clear after 40 warm-ups. Or a scan tool will do all of the above. You living in New york, maybe did some driving on salted roads? That will screw up a lot of border line electronics. Check the O2A fuse, too. probably not it, but worth just looking. It's an easy replacement. Can't find the P/N it yet though. Just have the harness numbers.
 

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P/n may be 12565397. Having a fit getting this confirmed, though. It is pre cat.
 

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Resident Guinea Wop
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Discussion Starter #10
aw crap that code came back
i wonder if salt or something is messing with the ocnnector

anyone have a location/diagram of this dealy
 

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It is the driver's side. Get some electric contacts cleaner, too. Dont get any on the sensor, but on the connections. These guys have no idea how lucky they are to have to not deal with salt. :nono:
 

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before you change out that sensor, make sure your gas cap is on tight. make sure it clicks at least 3 times. i had that code pop up for a while until i heard about the gas cap. once i did it and cleared it never had the problem again. that happened last year when my g/f didnt tighten the gas cap, and no problem since.
 

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Resident Guinea Wop
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Discussion Starter #15
before you change out that sensor, make sure your gas cap is on tight. make sure it clicks at least 3 times. i had that code pop up for a while until i heard about the gas cap. once i did it and cleared it never had the problem again. that happened last year when my g/f didnt tighten the gas cap, and no problem since.
I wish it was that simple. I do triple check my gas cap when I fill up, click, click, CLICK. Just ran out and clicked it a few more times.

But, the way I understood it, P0440 is the Gas Cap Evap code
 

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All these emissions things go bad so fast, are so sensitive and so expensive. :nono:
 
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