Oxygen sensor codes: Is O2 Sim failing?
#1
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Oxygen sensor codes: Is O2 Sim failing?
So I have codes for both rear o2 sensor (PO138 & PO158 Circuit High Voltage).
Since O2 sims completely rule out signals from the rear o2s, I can only assume the o2 sensors aren't the problem. Correct me if I'm wrong, but from the description of the codes and the way the o2 sim is wired in, it sounds like the o2 simulator is failing.
Of course, voltage looks fine when I monitor them with my scanner.
If I do need a new simulator, good luck finding one. Damn!!! I would hate to replace these rusted a$$ cats!!!! Good thing my smog is not due until August!!
Anyway, I need you electrical gurus to verify my initial diagnosis on the cause of the codes.
Thanks
Since O2 sims completely rule out signals from the rear o2s, I can only assume the o2 sensors aren't the problem. Correct me if I'm wrong, but from the description of the codes and the way the o2 sim is wired in, it sounds like the o2 simulator is failing.
Of course, voltage looks fine when I monitor them with my scanner.
If I do need a new simulator, good luck finding one. Damn!!! I would hate to replace these rusted a$$ cats!!!! Good thing my smog is not due until August!!
Anyway, I need you electrical gurus to verify my initial diagnosis on the cause of the codes.
Thanks
#3
well...if you had O2 sims properly wired and got no codes, and you did NOT change the wiring yet you get rear O2 codes now, then yeah either your sims have gone bad or the FRONT O2s are measuring out of tolerance relative to the rears...how are they wired?
Last edited by Amerikaner83; 06-04-2013 at 12:48 PM.
#5
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Before the ECM harness plug. Per this write-up:
http://forums.maxima.org/5th-generat...tallation.html
I've had this simulator for years. No problems until now...
http://forums.maxima.org/5th-generat...tallation.html
I've had this simulator for years. No problems until now...
#8
if you have O2 sims, or one sim with dual output, this code is telling you that they are no good assuming that you had it installed with no codes before. its not a heater circuit code so the O2 sensor is still ok.
#10
I know this may not be it, but about a month ago I had all my 02 sensors replaced. Two days later the Check Engine light came on. I took it back to the shop and their basic reader brought up the code for O2 sensors. We checked it again with a more advanced one and got that the gasket is leaking air, which in effect is giving us the O2 sensor code.
Just a thought.
Just a thought.
#12
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I know this may not be it, but about a month ago I had all my 02 sensors replaced. Two days later the Check Engine light came on. I took it back to the shop and their basic reader brought up the code for O2 sensors. We checked it again with a more advanced one and got that the gasket is leaking air, which in effect is giving us the O2 sensor code.
Just a thought.
Just a thought.
#15
assuming that you cut the signal wire to the O2 like you said, the problem is in either the wiring or the sim. V=IR so if you have high voltage, the problem is that you have too high resistance at some point in the circuit. It could either be a wiring/soldering problem or the sim. Can you remember where you got the sim from and possibly check if they have a resistance reading?
Last edited by Gemner; 06-04-2013 at 01:37 PM.
#18
Don't thread jack, Travis. You've been around long enough to know how to search. DO IT
#19
i bought my O2 sim dual output from here and it's been on my 02 6spd with obx headers for about 2yrs now without any issues
http://www.3sx.com/store/comersus_vi...?idProduct=769
http://www.3sx.com/store/comersus_vi...?idProduct=769
#20
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i bought my O2 sim dual output from here and it's been on my 02 6spd with obx headers for about 2yrs now without any issues
http://www.3sx.com/store/comersus_vi...?idProduct=769
http://www.3sx.com/store/comersus_vi...?idProduct=769
#23
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Ordered and installed simulator from 3SX Performance Automotive. Old simulator looked burnt from being inside engine bay for all those years. Wiring looked OK.
Did drivecycle, reset all monitors. Smogged vehicle. Problem solved.
Thanks to all of you who helped out!!!
Did drivecycle, reset all monitors. Smogged vehicle. Problem solved.
Thanks to all of you who helped out!!!
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