Yet another O2 sensor code, PLEASE HELP

AlanEdwards

Registered User
With GREATLY APPRECIATED HELP, I've taken care of all codes it was throwing, but there's still another that I can't figure out. I've got a 94 SC and it's giving a 172 code.

The EEC IV code book reads "lack of O2 switches, indicates lean rear side."

Is this telling me that there is a 3rd O2 sensor at the rear cat? If so I can't find it. Besides, I thought that I've only got 2 O2's, one before each front cat. My exhaust is all factory original.

Please help!!!!!

Thanks,
Alan
 
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best to chang all at one time,i think, not sure you have one behind muffler,should be 3 on it.
 
Which muffler?

Thanks, but behind which muffler? Total on the exhaust I've got 2 front cats, with the pipes going into 1 rear cat (which I think doubles as the resonator), then the pipe splits, then at the rear is a muffler on each side.

I know this is factory standard and most of you guys know all this, but I just wanted to clear it up, per the last reply.

Behind which of the 2 mufflers are you talking about?

Thanks
 
mine is a stock 89 i have 2 at the cats one behind muffler is 2 pipes going in muffler and 1 comming out and split into dules.mine is behind the muffler.3 on it.
 
Hey Alan, I called Rick Cunningham today and he said that the 94 doesn't have a rear O2 sensor, just the left and right like the earlier ones did and only the V8 had the rear O2 sensor. So, how could we have gotten a 172 code? It doesn't make sense unless it means something different on the SC and it wasn't listed correctly in my book. We both counted the beeps and flashes so we've got the right number. :confused: What else could a 172 code mean?
 
Have you tried swapping the O2 sensors right to left?
If defective Bosch O2 sensor it would then give code 176 (for left side).
(try NGK's O2's from sparkplugs.com)
 
Hey Alan, I called Rick Cunningham today and he said that the 94 doesn't have a rear O2 sensor, just the left and right like the earlier ones did and only the V8 had the rear O2 sensor. So, how could we have gotten a 172 code? It doesn't make sense unless it means something different on the SC and it wasn't listed correctly in my book. We both counted the beeps and flashes so we've got the right number. :confused: What else could a 172 code mean?

I show the 172 error code as "O2 sensor fault - lean bank #1" ? I would definetely switch the two sensors and see what happens. Short of that I would throw a new one in, or did I miss that already?


Ira
 
Thanks much. I'll try switching them and see what happens. This possibility sux, cuz I just replaced both of them in the last couple of months, about 3 weeks apart.

Mike, are you doing anything tomorrow morning (Saturday morning)? If not maybe I'll come over and see what the code says again, after I switch them. I can't bring beer this time, for I work at the hospital at 2 pm. It just wouldn't do, with me walking into a patient's room tipsy, LOL. Maybe I'll bring breakfast though. how does that sound?

What time is too early for you?

By the way, which is bank #1, left or right? And by left, I mean the driver's side. The car's left, not your left as you're looking at it with the hood up, LOL.

Thanks,
Alan
 
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#1 is drivers side,i belive any bosch product works fine on forigen cars ,not on our cars,being ford, chevy.ect.
 
put bosch plugs in my S10,showing ignition missfire,replaced with ac delco cured problem,run bosch in toyota 4 runner,runs great,tried them in the sc same thing as in S10,back to motorcraft in the sc,no more problem.i belive bosch and ngk are really for the forigen cars.
 
put bosch plugs in my S10,showing ignition missfire,replaced with ac delco cured problem,run bosch in toyota 4 runner,runs great,tried them in the sc same thing as in S10,back to motorcraft in the sc,no more problem.i belive bosch and ngk are really for the forigen cars.

I'm not going to argue with you. Everyone runs what they feel works best for them. I only know I run Bosch O2 sensors and my cars seem to run pretty well. Depending on the length of the pigtail you need I would recommend part numbers 15716, 15717 or 15718.

[shrug] ymmv

Ira
 
ira,im not argueing with you or trying to, im just telling my experence with bosch parts. sorry if you felt i was.im not good with abrevation, what is that ymmv or whatever it was mean.
 
My experience with NGK's O2'S is an extra one-two extra miles to the gallon vs Bosch.
I've read due faster switching. (in my test both were new)
 
Autozone and Advanced sells Bosche. Are there any stores that sell NGK O2 sensors, that anyone knows about?
 
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ira,im not argueing with you or trying to, im just telling my experence with bosch parts. sorry if you felt i was.im not good with abrevation, what is that ymmv or whatever it was mean.

It's not an argument. Just a different experience. What works for me may not always work for someone else and vice versa. Anyway, now I am intrigued when Chris says he uses NGK's and gets better fuel mileage. Now that would make me try them the next time I switch them out.

Oh, and ymmv = your mileage may vary :p
It's one of the few I know :D

Ira
 
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