Contour Enthusiasts Group Archives Forums General Troubleshooting O2 sensor bank 1 sensor 1 location?

I've had a CEL for the last 2 months or so, it goes away for a couple of days and then comes back, but it's gotten worse and now it's pretty much always on. I can clear it and it comes back within a day or so. It's a P1131 which my scanner says is "O2 Sensor Circuit Low Voltage Bank 1, Sensor 1".

I also notice a sulfur smell after driving a while, particularly up a long steep hill (which I do every day) - is this due to the computer ignoring the bad O2 sensor and running a pre-computed value (presumably a too-rich value)?

Should I just go ahead and replace the sensor or is there something else it might be? And which sensor is B1,S1 - the one at the front of the engine near the radiator, or the rear (there's only 2 O2 sensors on the V6, right)?

Thanks for any info

definitely the sensor. i had the same code for two months and - after replacing mine - the code went away. haven't had a code since.

the sensor is the one by the firewall. IT IS A PITA to get to. if you decide to do it yourself, look for How-Tos on this board. i found a couple before i did mine. You WILL need TWO universal joints. wasted alot of time before i got the second one. :rolleyes:

Thanks, it's the rear one, eh? Yep, it looks like a pain to do alright. 2 universal joints (for the ratchet wrench I presume)?

Dealer wants ~$100 to install the sensor, I might just let them do it since it's a PITA ..

I'll search the How-Tos, thanks again.

I did it with a sensor socket, an extension, and a U-joint on a 3/8" ratchet. Oh, and a cheater bar and rubber mallet.

Use the "Search" feature for P1131 and you'll get plenty. Or, use my procedure... The cheater bar is the essential part .

i was quoted $150 for the sensor and at least $90 for labor. i figured that equalled out to about 8 hours of my time.

btw, the sensor can be had for $87 if ordered online . be sure to give them your calibration code from the sticker on your door.

Well I just had the dealer replace the O2 sensor - they wanted $95 labor to install and after looking at what was required I figured that my time and knuckles were worth more than that. Of course, I had to buy one of their "genuine Motorcraft sensors" at $115 or they wouldn't do the job ...

But it's in, and after 1 day I still don't have the CEL and the car does seem to run better. So I guess I'm happy.

Thanks to everyone for their help. Now if I develop a problem with the Bank 2 sensor maybe I'll do that one myself, it looks to be a lot easier.

Also, I've seen various posts here regarding the number of O2 sensors of the V6, some people say 2, some say 4. I asked the service rep and she said "2" but she's not a mechanic. My Haynes and Chiltons manuals seem to indicate only 2. Does anybody here definitively know the answer? As in "I've replaced all 4 so I know it's got 4" or something like that. And if you do think there's 4, where are those other 2? The 2 I can see are in the exhaust pipes off the 2 heads.

thanks as always for the good info.

95 Duratech has 2 O2 sensors (OBD-I)
96+ Duratech has 2 O2 sensors (OBD-II)

Haynes (and presumably Chilton) is based on a teardown of a 95, thus the 2 sensor reference

The extra 2 are past the exhaust manifolds on each bank

>>Also, I've seen various posts here regarding the number of O2 sensors of the V6, some people say 2, some say 4.<<

My 98 Mystique V6 has 4 O2 sensors. There is one on each manifold before each precat and one just downstream of each precat. AutoZone sells them for about $69 each.

Jeff