1996 850 GLT O2 Sensor Replacement Attempt

osmium · Post by **osmium** » 23 May 2015, 15:45

I've had the 850 for almost 6 years and put about 72k mile on it.

Recently, I got a check engine light and read a P0141 code. Erased it and it's come back. Since I've owned the car, I haven't had any of the O2 sensors replaced.

Before buying the replacement Bosch sensor, I decided to make sure I could get the bolts off the plate below the O2 sensor. (Car's been in New England for its entire life, so bolt are sometimes tough to get off.) So I PB blasted them and waited a while. When I came back to try an loosen them, two turned pretty easy but never come out. They just keep spinning in place. Are what's holding the thread something like a PEM nut and is just turning?

-os

Post by **osman** » 23 May 2015, 18:29

The heat shield? Im confused. You shouldnt need to remove it, O2 codes are usually a vacuum leak or lean/rich condition.

osmium · Post by **osmium** » 23 May 2015, 21:15

osman wrote:The heat shield? Im confused. You shouldnt need to remove it, O2 codes are usually a vacuum leak or lean/rich condition.

Thanks for the reply.

I thought the P0141 code meant the rear O2 sensor was bad.

But, your reply reminded me that about a year ago I got a code (don't recall what) that wound up being the elbow in the intake manifold. I replaced the vacuum tubing and rerouted it. Turns out that the end that connected to the flame trap assembly had slipped off.

Put it back on. Will see if the code returns.

Thanks for your help. Won't have to deal with those bolts right now.

Post by **misha** » 24 May 2015, 15:56

osmium wrote:...I thought the P0141 code meant the rear O2 sensor was bad...

Yes...the rear one.

draser · Post by **draser** » 24 May 2015, 16:02

That's an o2 sensor heater code.

draser · Post by **draser** » 24 May 2015, 17:06

So if you have or can get an ohm meter measure sensor heater resistance at the connector. If you read some low resistane there then sensor is good.

osmium · Post by **osmium** » 27 May 2015, 17:30

draser wrote:So if you have or can get an ohm meter measure sensor heater resistance at the connector. If you read some low resistane there then sensor is good.

Got the vacuum hose back on.

Check engine light came back on couple days later. - Found two codes:P0141 and P0136.

I take it these point to the rear sensor.