[cjmahone66]

i've searched, can't find the answer to my problem, but please redirect me if you know of a thread already like mine. thanks.
2003 Ford Escape. V6, automatic, 4WD, 83k miles.

Problem:
one day the check engine light came on, i hooked up my OBD reader and it was throwing codes P0141 and P0161. these codes indicate a problem with the O2 sensors for both the forward and rear bank "downwind" sensors. to be clear, these are the sensors located AFTER the catalytic converters on each header.

i thought it was wierd that both of these sensors would go bad at exactly the same time, but i replaced them anyway. then i cleared the codes and took it for a testdrive. after about 10 minutes the light came back on. it's throwing the same codes again.
i thought the sensors might not be fully seated, or maybe they backed out? so i removed and reinstalled them. torqued to specs in my manual. still throwing same codes.
then i tried my best to trace the wires back as far as i could to make sure there were not any tears or shorts in the wires, everything looks good.

What do i do next? i'm still getting codes P0141 and P0161, though i'm pretty sure both sensors are fine. is there any way to test the sensors with a voltmeter or something?
is there anything else i should be checking? what would make both of these sensors get bad readings? thanks for any help.

 

[etrailer]

Examine the electrical harness from the sensors back to the vehicle. Check for melted or nicked wire insulation. If you did not clean the terminals when you disconnected the old sensors and installed the new, you should clean those and use some dielectric grease to keep them clean.

 

[cjmahone66]

Examine the electrical harness from the sensors back to the vehicle. Check for melted or nicked wire insulation. If you did not clean the terminals when you disconnected the old sensors and installed the new, you should clean those and use some dielectric grease to keep them clean.

i already traced wires back to main harness, couldn't find anything wrong with them. also cleaned terminals with brake cleaner and put fresh dialectric grease on them both times i installed them. didn't change anything.

 

[Manic Mechanic]

Look for a blown fuse that powers the heated oxygen sensors.

I'm not sure if the fuse is under the hood or in the vehicle.

Update: Look for the HEGO fuse (15A) under the hood.

 

[slavrenz]

Look for a blown fuse that powers the heated oxygen sensors.

I'm not sure if the fuse is under the hood or in the vehicle.

Update: Look for the HEGO fuse (15A) under the hood.

+1. It has to be something electrical. You were right in your suspicion that both sensors could not have gone bad at the same time. You could have saved some $$$ eace:

 

[cjmahone66]

fueses are all good.
i finally gave in and took it to my mechanic. he's had it for a few days and still can't find the problem either . talked to him yesterday and he said he had traced all wiring and couldn't find anything wrong with it. he's still trying to rule out everything else, but said that it's looking like the PCM isn't actually sending a signal like it should, even though it's still expecting one back from the O2 sensors. i might be in for a new PCM.

 

[R-code17815]

My parents Escape was doing the same thing, Replaced the fuse under the hood (HEGO) with a 20A and never had a problem again, that was over a year ago....

 

[wptski]

Either the wiring harness, fuse or PCM is bad for the heater circuit.

 

[slavrenz]

My parents Escape was doing the same thing, Replaced the fuse under the hood (HEGO) with a 20A and never had a problem again, that was over a year ago....

Seems to me that that is just masking the problem, rather than solving it. Something is causing a higher than usual current flow - while it may not be enough to burn out any wires (yet), I would never do that with a vehicle that I owned.

 

[R-code17815]

My parents Escape was doing the same thing, Replaced the fuse under the hood (HEGO) with a 20A and never had a problem again, that was over a year ago....

Seems to me that that is just masking the problem, rather than solving it. Something is causing a higher than usual current flow - while it may not be enough to burn out any wires (yet), I would never do that with a vehicle that I owned.

Well good for you....

It's still running like a champ, never had another issue. I guess on the internet everyone's a pro.
:horse:

 

[slavrenz]

My parents Escape was doing the same thing, Replaced the fuse under the hood (HEGO) with a 20A and never had a problem again, that was over a year ago....

Seems to me that that is just masking the problem, rather than solving it. Something is causing a higher than usual current flow - while it may not be enough to burn out any wires (yet), I would never do that with a vehicle that I owned.

Well good for you....

It's still running like a champ, never had another issue. I guess on the internet everyone's a pro.
:horse:

Wasn't looking for a confrontation, so maybe cool down a bit eace:. I'm just saying that it's not an ideal repair solution, and while it had no ill effects here, replacing fuses with higher rated ones is not generally a good idea.

 

[SUVord]

If an electrical circuit is nominated to draw a certain current of, say, 5Amps and suddenly it requires above 5 Amps, it means that circuit's potential diferrence has dropped, thus requiring more current.
So, this circuitry is at fault and needs some attention/repair.If left unattended and increased current flows through the circuitry, after a while the circuit will fry and so will the whole vehicle.
The use of a bigger amperage fuse is not a remedy but only and only an emergency fix.

Please, no experts here.Just common folks communicating with each other.
Have a nice week everyone.

 

[R-code17815]

Do what ya want, think what you want...I'm already tired of the know-it-alls on here

Good-luck op......

 

[cjmahone66]

PCM was replaced and that fixed it.

 

[SUVord]

PCM was replaced and that fixed it.

Thank you very much for posting the results.

 

[Zepp774]

So I'm up for renewal on my registration and I need to pass smog . My check engine light has been on for awhile and I have responsibly ignored it since driving has been good. Anyways the codes that are coming up are for all my oxygen sensors and my egr valve. Started checking my fuses and turns out hego fuse is blown. Put some new ones in and on the drive home it blew also ( although i did not unplug my battery ). So now I'm thinking it might be a similar problem to this thread. How much did the pcm end up costing you? Also wondering if because all my sensors are going off and only 2 of yours went off maybe it is a different issue. I'll start tracing some wires tomorrow to see if i'm grounding out.

 

[jbone2470]

Do what ya want, think what you want...I'm already tired of the know-it-alls on here

Good-luck op......

Wow, Your already sick of the know it alls? I think maybe chill out and take into consideration that alot of people on here know alot and just want to help.But don't get upset if someone disagrees with you and may have the experience to try to help you then either take it or leave it..
No need to get your panties in a bunch..This forum is to help people,yes some know alot, some don't.But we all learn from each other.No one knows it all, but some do have vast experience and are giving it to us for free..But if you don't like something then you can leave.But I would like you to stay, but only if we all can get along and peacefully respect ones opinions and not down anyone, that i assure you will not fly here..

Anyways I am glad to hear the OP got his/her problem solved.... eace: Now it's time for dinner... :beer:

 

[hworksinc]

So I'm up for renewal on my registration and I need to pass smog . My check engine light has been on for awhile and I have responsibly ignored it since driving has been good. Anyways the codes that are coming up are for all my oxygen sensors and my egr valve. Started checking my fuses and turns out hego fuse is blown. Put some new ones in and on the drive home it blew also ( although i did not unplug my battery ). So now I'm thinking it might be a similar problem to this thread. How much did the pcm end up costing you? Also wondering if because all my sensors are going off and only 2 of yours went off maybe it is a different issue. I'll start tracing some wires tomorrow to see if i'm grounding out.

You'll probably want to check the wiring to the O2 sensors for damage. You may have a failed O2 sensor as well. A PCM issue may cause the CEL to light up, but should not cause the HEGO circuit to draw more current or blow a fuse.

 

[npereza5]

Sorry to jump in I have a 2003 Mazda Tribute and its been throwing the same codes p0141 and p0161. I have replaced both 02 sensors and the pcm (used) and still they're not going away. They come back really quickly as pending codes and by the next key turn are straight dtc's. I inspected the connectors and harness all the way back to the pcm and cannot find anything. Am I missing something? Could anything else cause this in both down stream sensors? I did probe both white wires on each sensor and only 1 white wire would produce a 12v current the others produced nothing on the voltmeter which is why I changed the sensors but still getting the same codes.

I also checked the HEGO fuze and it is fine.

 

[03trib]

I also have an 03 tribute which threw an 0161 error first then after ignoring it also 0141. I have replaced o2 sensor bank 2 sensor 2 (aka left downstream 0161 error). I also have had problems with it not starting at all for long periods of time once its running I have no problems. I also swapped the HEGO fuse with my AC fuse -both 15A. I can clear the CEL it will pop back up within 10 minutes. It appears according to the torque app that both 02 sensors are still sending telemetry. 70K miles no maint except oil, air filter, battery, breaks, alternator, serpentine belt and now one 02 sensor. I'm looking at a PCM maybe. Please help can't afford mechanic.