1997 855 glt p0133, p0136, p0140

adamdrives · Post by **adamdrives** » 18 Jun 2015, 12:11

Hello All, my first post here but I am a long time lurker. Matthews is a great place to get intelligent advice.

The problem I am having is with my 97 wagon. I bought it a few years ago with a bunch of issues, and slowly fixed it up. I'm at the last stage of restoration, with a few nagging problems. For some reason, my (brand new, bosch) rear o2 sensor reads very low voltage. It will start off in the correct ~0.45 range, but quickly plummet to 0.02v. I thought maybe my sensor was a dud, so I replaced it with another--exact same problem. At the suggestion of a volvo tech and friend of the family, I installed a spacer to fool the rear o2. The same symptoms persist. As I reset codes and try new components, I have retrieved p0133, p0140, and most recently p0136. I believe the cat may be non-functional, it's an aftermarket unit that came with the car. Still, shouldn't the spacer eliminate that as a cause for rear o2 voltage issues? I'm nearing the end of my patience with this car. Is there anything I've overlooked?

Thanks in advance,

Adam

Post by **Ozark Lee** » 18 Jun 2015, 17:52

P0133 is a front sensor slow response code.

P0136 is a rear sensor low voltage code which tracks with what you observed.

P0140 is a rear no activity code which also tracks with what you observed.

When you replaced the rear sensor you said you used a Bosch sensor but was it a factory fit with the OEM plug or a universal? The universals have had a spotty record but most of the problems with them seem to go back to problems in the splice box. Your problems sound a lot like a wiring or connector problem.

The spacer won't do anything for a low or no signal situation on the rear sensor and, unless the catalytic converter rattles and sounds like it is full of gravel it is likely OK.

...Lee

adamdrives · Post by **adamdrives** » 18 Jun 2015, 19:17

Hi Lee, thanks for the reply.

I had the codes checked at a volvo dealership and they (p0133, p0140) were both for rear o2. This was confusing to me too, but I did a little digging around and figured it out. P0133 can be for front or rear sensors; front is Front HO2S Slow Response, rear is Rear HO2S Compensation. (Source volvotips.com). Regardless, it is only showing p0136 today after a low drive. In fact, p0136 came up as pending, and when I checked later it had cleared itself. However, I am still getting very low voltage at the rear o2. According to my hanynes manual, the rear o2 heater goes through fuses #7 and #82. I am not sure where 82 is. To answer your question, it is a bosch oem exact fit, 15062. In fact, it is the second brand new one I've tried after the first gave me these codes.

The cat doesn't rattle, but when I was removing the rear o2 sensor some chunks of the honeycomb substrate fell out, maybe a handful.

adamdrives · Post by **adamdrives** » 18 Jun 2015, 19:31

disregard

Post by **Ozark Lee** » 18 Jun 2015, 20:12

I don't think you have a heater problem since the heater circuit throws its own unique code for the heater failure. The honeycomb pieces are, however, troubling.

With the OEM fit Bosch you have done everything correctly and I don't have an immediate answer unless the honeycomb pieces have blocked off all flow around the sensor. Usually when a catalytic converter fails the car really runs poorly since it blocks off the exhaust flow. It isn't an emissions thing as much as it is an air flow thing. The rear sensor doesn't control the mixture, it really only serves as a tattletale on catalytic converter efficiency.

??????

...Lee

adamdrives · Post by **adamdrives** » 18 Jun 2015, 20:23

Ozark Lee wrote:Your problems sound a lot like a wiring or connector problem.

Are there any tests I can do on the wiring side? Resistance/voltage at connector?

adamdrives · Post by **adamdrives** » 18 Jun 2015, 21:58

Just to add to the frustration, after about an hour of driving the obd2 reported it was running in open loop due to "insufficient engine temp." Obviously, the motor was warm. The rear o2 now reads a steady 0.00v, even after clearing codes. p0136 is gone, now reads p0137, I'm not sure what the difference is. Could this problem be fuel related?

Post by **abscate** » 19 Jun 2015, 04:01

It sure sounds like that aftermarket cat is the culprit. The hard part will be finding a used one..junkyards aren't allowed to sell them. Look for a part out here.

A new one will make you cry.

adamdrives · Post by **adamdrives** » 22 Jun 2015, 21:02

I've installed a new (this is the third) bosch sensor and no codes have returned. I'll have to wait for the monitors to clear to be sure this is a solution but normally I would at least have a pending cel by now. Curious thing is the rear o2 still reads very low. Not sure what to make of that.