Whoh, did my truck just fix itself??

Hey guys, once again, I'm back on the subject of my supposedly fried 02 Sensors. So.. I was drivin around a few minutes ago, and i just happened to look down and see that my check engine light was off, for no reason, whatsoever. I haven't cleared any codes in about a month now. Originally, it was on because both B1S2 and B2S2 O2 sensors were supposedly fried, but how can it just go away like that? I reset my MPG, and I'm gettin about 16-17 just easin around town. So here are the first 2 things that have come to mind..

1. The cold. I thought it could be leaning out the mixture, because its around 25 here tonight, and the MIL was on earlier today.

2. Friday night, i got tired of my amp going into protect mode because i had 3 speakers hooked up in series, and the ohm level was below my amp's capabilities. So, tired of it sucking too much juice and whooping up on my alternator, which apparently couldn't keep up (there's been a many a time where I've had to stop, kill my truck, and then go again because my voltage meter was chilling on 12), I redid my setup by hooking up the two speakers in the sealed box underneath the backseat in parallel, while leaving the one behind in it's own circuit. Now my voltage meter always reads above 14. So MAYBE its delivering a better spark, and MAYBE getting every component the adequate voltage they need to function correctly.

My codes were (if i remember correctly) P0172-Bank 1 Rich and P0175-Bank 2 Rich.

It's gonna suck if all this is some horrible trick my truck is playing on me. Lol So what do you guys think?

Your secondary O2 sensors (B1S2 & B2S2) only monitor cat efficiency. They won't cause your truck to run rich or affect your mileage.

FYI, wiring your speakers in series increases their ohm rating.

I got alldata dude, would you like me upload the service sheets for the P0172/5 codes? and sorry i did get parallel and series mixed up for some reason. my bad.

always good to run your subs parallel and get a bigger alternator
i had that problem with the engine light to...after a month it went away....5 months later came back...went away in a month....had nomore problems after that....im sure your ok man

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Originally Posted by devin_deville

I got alldata dude, would you like me upload the service sheets for the P0172/5 codes?

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No need, I'm familiar with those codes. They are generated by the primary O2 sensors (B1S1 & B2S1), not the secondary sensors that you listed. You have either not enough air or too much fuel in your mixture. Check for a restriction in your intake, dirty filter, etc. Also check for high fuel pressure, leaking injectors, etc.

i've done all that already, like 6 months ago. i just haven't gotten around changin the old ones out.. i'm just wonderin why it all of a sudden went away, like it fixed itself.

After a certain number of igniton cycles the history DTC's will clear. A type A DTC will sometimes set and turn the light on the very first cycle there is a failure. Even if the failure is gone, the light will remain on.

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Originally Posted by devin_deville

Did my truck just fix itself?

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why yes, yes it did


didnt u know vehicles made after 1998 have an ability to heal themselves after a period of time?
Much like the human body.
The only reason most people fix their cars when they break is because they dont want to wait on the healing process as it usually takes about 6 months, hope this helps :ugh2:

False alarm.. MIL's back on. i thought i was gonna get to save some money but nevermind. i think its because my negative battery cable was loose, my truck kept idlin rough and sometimes it wouldn't crank till you popped the hood and jiggled the cable. i think it reset my pcm

See?