P0133 Code, Brand New Bosch 15097, 1997 850

GregK · Post by **GregK** » 01 Aug 2008, 12:19

Thanks everyone for this site, it has been very helpful! I'm having trouble with my front oxygen sensor in a Canadian 1997 Volvo 850 non-turbo, manual transmission. At first I replaced the rubber elbows, and checked the MAF and cleaned some of the electrical connections, but the front sensor code kept coming back, so I replaced it with a Bosch 15097 from FCP.

Now the lamda light comes on after about 3 days driving, and the scanner reads P0133. It has been reset multiple times, both at a garage with OBDII and by me disconnecting the battery for more than 10 minutes. I have tried the sensor with and without the extension (which does not seem to be needed on my car.) Nothing works, the code keeps coming back.

Wrong type or defective sensor? Any ideas? Thanks for your help.

chuckcintron · Post by **chuckcintron** » 01 Aug 2008, 12:33

Usually this code is a result of an incorrectly wired or defective sensor, yes. The heater circuit is the culprit.

But, if we knew the sensor to be good the other things to look for are:

- faulty MAF
- faulty fuel pressure regulator (*)
- faulty EGR system (not sure if CA version of this car has EGR or not...)
- vacuum leak
- exhaust leak (before the sensor, of course)
- fuel injector(s) out of spec
- bad ECU (unlikely)

(*) when you pull the O2 sensor if it looks like it's been barbecued, check to see if you are in spec on fuel pressure. If the car is running too rich you can cook/ruin the front O2 sensor, although it takes a bit of time for that to happen.

-Chuck

GregK · Post by **GregK** » 02 Aug 2008, 09:42

Thank you, that helps to narrow it down, the most likely is the sensor. Is it the correct sensor? I didn't know about eEuroparts before all this, but now I see they have two different Bosch front oxygen sensors, and Bosch 13373 has a note that it is for manual transmissions. Maybe the 15097 doesn't work properly with my car?

chuckcintron · Post by **chuckcintron** » 02 Aug 2008, 20:24

Not sure, but you need to order the correct part for your car. When they ask about auto vs. manual it's for a reason...different ECUs.

I've found sparkplugs.com to be pretty accurate; maybe double check with what they call out as the correct component.

-Chuck