1995 850 2.4l P0133 (O2 sensor)

Post by **wheelsup** » 13 Nov 2015, 11:10

Car has 185k. Original O2 sensors.

Got an O2 code, don't remember what it was, I think it was for the rear. Replaced front O2 sensor with Bosch from FCP as I read that is typically the one to fail. Now getting P0133. Should I replace the rear as well or is there something else going on?

I dislike guessing on these expensive parts but without a scope I'm not sure what else to do!

Post by **erikv11** » 13 Nov 2015, 11:25

Did you get a 15097 for the front O2, the direct fit one?

If so, time to start looking at some of the other causes of O2 codes: wires and connectors to the sensor, vacuum leak (intake), exhaust leak, fuel pressure (I think pressure too low will give p0133, check the FPR).

Post by **wheelsup** » 14 Nov 2015, 14:28

Yes it was the Bosch from FCP. So the code is for sure for the front sensor? Hmm.

The previous code was for the rear sensor slow to respond, can't remember the exact code #, but I kept reading that the front one is the one that normally goes.

I threw out the old O2 stupidly. Wonder if the 'new' front is bad or would a bad rear throw the front code as well?