CEL for O2 Sensor '95 850

LightingZ06 · Post by **LightingZ06** » 10 Nov 2008, 18:03

Hey Guys,

My CEL keeps coming on and displays:

P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

and sometimes but not usually:

P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)

Now, I have not seen a decrease in my gas mileage over the past week and a half since this been going on and its always around ~24-25 MPG mixed driving. Car is not sluggish or anything, basically nothing has changed except the light keeps coming on. Does this mean I need to replace the oxygen sensor, or can I try something else before breaking down and buying the damn thing.
How easy is this to do yourself?

larryh · Post by **larryh** » 10 Nov 2008, 18:33

I don't know...For something like this, it might be a good time to see your fine local independant volvo shop. I bet it'll be cheaper than you throwing parts at it. Those sensors are not cheap.
It might not hurt to give the sensor connections a look and possibly a cleaning first though.

Post by **Ozark Lee** » 10 Nov 2008, 18:37

You might get lucky and just have a dirty connector but usually the heater malfunction code means that the heater circuit in the O-2 sensor croaked. Unplug the sensor and use an ohmmeter between the two white wires. It should have very low resistance - almost like a short.

...Lee

LightingZ06 · Post by **LightingZ06** » 10 Nov 2008, 19:07

Hmm,

. I looked at directions at Bay13 and this is too much of a pain in the ..... I'd rather have someone else do it. Any ideas what to expect to pay at an independent shop for this replacement.

mbsl98 · Post by **mbsl98** » 12 Nov 2008, 10:48

Quick related question. Is bank 1, Sensor 2 on an 850 the front or the rear O2? I always get them mixed. I assume it is front due to heater code? Sensor 2 just sounds as if it should be teh rear.

Post by **Ozark Lee** » 12 Nov 2008, 13:33

It is indeed the rear.

...Lee

LightingZ06 · Post by **LightingZ06** » 13 Nov 2008, 19:34

actually decided i'll tackle this myself. Part probably wont get here til next week. Question now is how long can I keep driving like this? and will this cause any problems to the cat or the car itself.

Thanks

Post by **Ozark Lee** » 13 Nov 2008, 20:59

It will throw the motor into a partial limp mode (It will guess a mid range on fuel trim) and inhibit performance but if you get to it within a reasonable period of time there should be no long term consequences.

...Lee