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Persistent PO135 O2 Sensor Code

S

Scorpion8

Hard-core CEG'er
Joined
Jul 10, 2008
Messages
1,620
Location
Juneau, AK
So, I checked my upstream O2 sensor in this thread: http://www.contour.org/ceg-vb/showthread.php?t=33992 and this one: http://www.contour.org/ceg-vb/showthread.php?t=34440. Brand new O2 sensor, installed, cleared the code and drove to work just fine. Get in at lunch and it's back. Stop at my destination, clear it, and it comes back while returning to work. Clear. Back. Clear. Back.

It's the same code each time, and only that code. What else could be the issue here? Any help would be appreciated.
 
Some reasons for a P0135 code could be:

1) O2 sensor contaminated (due to presence of silicone in fuel). Have you been putting additives in the fuel?
2) O2 sensor signal circuit open. Check connector or wiring for open circuits.
3) O2 sensor damaged or failed.
4) PCM has failed.
 
Thanks.

1) I have added a bottle of fuel injector cleaner, but that's all. It doesn't affect my other cars.
2) It'll clear, and stay off for awhile. Wouldn't an open circuit come right back?
3) brand new sensor. That doesn't mean it couldn't be bad, but unlikely?
4) Would a bad PCM show other codes, and not just this one repetitively?

Thanks for the help!
 
Last time I re-set it, it drove quite a while before faulting out again. Each time is a different distamnce, and that got me thinking that maybe one of the pins is intermittant. I'm going to try beding them each slightly inward to make more positive contact and see if that helps. Are the connectors replaceable?
 
As an update and future reference, last night I bent all four connector pins inward towards the center of the square a few thousanths of an inch to make a x-pattern spring. Hoping that will enhance the pin-to-plug contact and stop the sensor from faulting out. I also gave the plug-end a good hosing with electrical contact cleaner, and then Deoxit ProGold which is an electrical connector lubricator-preservative.

So far so good. I drove all the way into work without the CEL coming back on, and we have quite a few "test enhancement potholes" thoughfully left by DOT just for testing purposes like this to make sure you did your work right.

So far so good. I'll post an update if anything else occurs.
 
Well, the connector on the radiator frame between the engine and frame isn't it. I even bent them in a little bit more, reset the code, and drove fine. It always drives fine the first time. The 2nd time you drive it, it'll fault out. Now it's just getting dang annoying. The hunt continues.
 
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