Code P1131 - 02/19/04 02:21 AM
Does anyone know what this code means and how to fix it? I just got back from Autozone and thats the code they pulled. Thanks.
Re: Code P1131 - 02/19/04 02:28 AM
yes i had this code pop up so many times. It an oxygen sensor, that kept on making my CEL pop on. I have a computer diagnostic tool though, so it's easier and free for me 
. I believe that it's sensor 1 in bank 1. I just gave mine some time, because this is a common error, and my CEL went away by itself after a week or two, and it hasn't come back on in over a month.
. I believe that it's sensor 1 in bank 1. I just gave mine some time, because this is a common error, and my CEL went away by itself after a week or two, and it hasn't come back on in over a month.
Re: Code P1131 - 02/19/04 02:32 AM
Mine must really be going bad then. It will come on for a day or so then go back off for a day. Oddly enough I have an O2 sensor for the car sitting right in front of me. Are you sure its sensor 1 bank 1? Which one is that?
Re: Code P1131 - 02/19/04 02:52 AM
I am now sure that it is. I went to diagnosticdialog.com and entered it, and this is what came up.
Diagnostic Trouble Code Description
--------------------------------------------------------------------------------
Trouble Code: P1131
Vehicle Qualification: Ford Contour
Description: Lack of HO2S Bank 1 Sensor 1 Switches - Sensor at Lean Limit
I don't have a clue though, as to where it is or how to replace it, i never did.
Diagnostic Trouble Code Description
--------------------------------------------------------------------------------
Trouble Code: P1131
Vehicle Qualification: Ford Contour
Description: Lack of HO2S Bank 1 Sensor 1 Switches - Sensor at Lean Limit
I don't have a clue though, as to where it is or how to replace it, i never did.
Re: Code P1131 - 02/19/04 02:53 AM
So it isn't even necessarily that the O2 sensor is bad...
Re: Code P1131 - 02/19/04 02:55 AM
Nope not necessarily. How long has your been on, or coming on and off?
Re: Code P1131 - 02/19/04 03:21 AM
I had the [censored] C&L MAF on for a while, but took it off because I only had it there while I couldn't find the stock one. Then I switched back and now it comes on and off pretty regularly. It's usually on more than it's off, but I find when I get lower on gas it usually comes on then when I fill up it'll go away.
Re: Code P1131 - 02/19/04 04:21 AM
So I found this online:
P1131 Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 1)
P1137 Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting rich due to an overly lean air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.
Bank 1 refers to the bank of cylinders containing Cylinder #1.
Sensor 1 refers to the O2 sensor closest to the exhaust manifold.
Sensor 2 refers the O2 sensor downstream of the catalytic converter.
So what should I do if thats saying it doesn't mean the O2 sensor has gone bad? I have a filter, but the MAF is stock. I do have a different tube connecting the MAF to the TB though. Could that be it? Or just the filter? Should I just get a chip or Apexi SAFC? haha
P1131 Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 1)
P1137 Lack Of HO2S1 Switches, Lean (Bank 1, Sensor 2)
These codes usually do not indicate a problem with the O2 sensor. Rather, the O2 sensor is correcting rich due to an overly lean air/fuel ratio. Check Base Engine Idle, EGR, Fuel System and Air Induction System.
Bank 1 refers to the bank of cylinders containing Cylinder #1.
Sensor 1 refers to the O2 sensor closest to the exhaust manifold.
Sensor 2 refers the O2 sensor downstream of the catalytic converter.
So what should I do if thats saying it doesn't mean the O2 sensor has gone bad? I have a filter, but the MAF is stock. I do have a different tube connecting the MAF to the TB though. Could that be it? Or just the filter? Should I just get a chip or Apexi SAFC? haha
Re: Code P1131 - 02/19/04 04:31 AM
If the oxygen sensors have been in the vehicle for over 60K (up to 100K, which is the recommended replacement interval for OBD-II cars), they should probably be changed anyway.
Especially given how "fragile" the pre-cats are. Not that I'm suggesting that a worn out, sluggish oxygen sensor could cause a pre-cat to fail....I'll leave that to Bosch[1], but it is rather interesting, isn't it, that I got a code P1151 (bank 2 oxygen sensor not switching/lean limit), drove around with it for about 300 miles, replaced the sensor, and shortly after I replaced the bank 1 oxygen sensor, I got a P0430 (bank 2 catalyst efficiency below threshold).[2]
Then again, it's also rather suspicious that I made the P0430 code "go away" by cleaning the throttle body with the engine running[3], and then passed the emissions check with the lowest readings the car has ever gotten. I also replaced the bank 1 oxygen sensor, figuring that if the bank 2 sensor had crapped out, bank 1 can't be far behind.
[1] Bosch states that a faulty oxygen sensor can cause catalyst failure. Maybe they're overstating the case to sell a few more, but my bank 1 sensor was really wacked. Clear the P1151 code and it'd come back within two drive cycles.
[2] The catalyst monitor does not run if there are any pending or active oxygen sensor codes.
[3] See my post about this here
Especially given how "fragile" the pre-cats are. Not that I'm suggesting that a worn out, sluggish oxygen sensor could cause a pre-cat to fail....I'll leave that to Bosch[1], but it is rather interesting, isn't it, that I got a code P1151 (bank 2 oxygen sensor not switching/lean limit), drove around with it for about 300 miles, replaced the sensor, and shortly after I replaced the bank 1 oxygen sensor, I got a P0430 (bank 2 catalyst efficiency below threshold).[2]
Then again, it's also rather suspicious that I made the P0430 code "go away" by cleaning the throttle body with the engine running[3], and then passed the emissions check with the lowest readings the car has ever gotten. I also replaced the bank 1 oxygen sensor, figuring that if the bank 2 sensor had crapped out, bank 1 can't be far behind.
[1] Bosch states that a faulty oxygen sensor can cause catalyst failure. Maybe they're overstating the case to sell a few more, but my bank 1 sensor was really wacked. Clear the P1151 code and it'd come back within two drive cycles.
[2] The catalyst monitor does not run if there are any pending or active oxygen sensor codes.
[3] See my post about this here
Re: Code P1131 - 02/19/04 04:35 AM
By the way it's been my experience, at least with the V6 Contour, that oxygen sensor "lack of switch/lean" codes are caused by a bad oxygen sensor.
I've gotten the code 4 times among two different V6 Contours, and each time, yes, it was the oxygen sensor.
Now if BOTH oxygen sensors were reading lean I might suspect some other problem like an intake manifold leak.
I've gotten the code 4 times among two different V6 Contours, and each time, yes, it was the oxygen sensor.
Now if BOTH oxygen sensors were reading lean I might suspect some other problem like an intake manifold leak.
Re: Code P1131 - 02/19/04 05:04 AM
So you're saying replace the bank 1 oxygen sensor before I go worrying about anything else, correct? Which one is the one for my code then? I mean where is it located on the car. I actually have an O2 sensor sitting right here in front of me that I had from years ago for this car. I never ended up replacing it because the engine blew up, haha, go figure.
Re: Code P1131 - 02/19/04 01:21 PM
Originally posted by RyeLou:
So you're saying replace the bank 1 oxygen sensor before I go worrying about anything else, correct? Which one is the one for my code then? I mean where is it located on the car. I actually have an O2 sensor sitting right here in front of me that I had from years ago for this car. I never ended up replacing it because the engine blew up, haha, go figure.
If you have a V6, Bank 1 Sensor 1 is the firewall side, upper. remove the coil pack to replace it.
P1131 is a sensor problem in most cases.
Steve
Re: Code P1131 - 02/19/04 01:30 PM
I should be able to remove the coil pack myself. I've never done it but it doesn't look too hard. Any tips? Maybe I'll give my spark plugs a check while I'm in there and see if they're alright, too. Thanks for the help. I'll probably get to it next week. What a spring break I have planned for me now! 
Re: Code P1131 - 02/19/04 03:02 PM
If your running double-plantinums take notice of the platinum pad on the ground electrode. I just pulled mine and that platinum on all three plugs (Bank 1 neg firing)almost gone with only 13k on the them. I rotated bank 1 & 2's plugs. Seat of pants feel was noticed. Once I get the new OBD II misfires info figured-out, I'll be able to tell for sure what's really doing.
I upgraded to Alex Peppers (OBD-II.com)latest Rev. software and it's showing a whole new set info that wasn't there before. e-mailed Alex and his reply was something to the effect if it PCM responses it's valid? Even though mines a 98 those codes are in there up to the 2000 model? I think that what's he tring to say?
If you want I can PM you (cut/paste) info from my 98 CD manual? Just Pm me. (Ref 1131/etc) It will add fuel to the confusation. how The Ford mechanics fix anything is amazing. I guess that's why they also have a seperate emissions manual?
I only have 50k on my car I'm not looking forwaqrd to this pre-cat/O2 sensor snafu. Bring on the common rail diesels low end torque!!!!! The drivers in Europe are lucky!
Paul
I upgraded to Alex Peppers (OBD-II.com)latest Rev. software and it's showing a whole new set info that wasn't there before. e-mailed Alex and his reply was something to the effect if it PCM responses it's valid? Even though mines a 98 those codes are in there up to the 2000 model? I think that what's he tring to say?
If you want I can PM you (cut/paste) info from my 98 CD manual? Just Pm me. (Ref 1131/etc) It will add fuel to the confusation. how The Ford mechanics fix anything is amazing. I guess that's why they also have a seperate emissions manual?
I only have 50k on my car I'm not looking forwaqrd to this pre-cat/O2 sensor snafu. Bring on the common rail diesels low end torque!!!!! The drivers in Europe are lucky!
Paul
Re: Code P1131 - 02/19/04 09:31 PM
If you use an NTK sensor like the OEM one an oxygen sensor socket WILL fit back there for installation/removal, contrary to what the how-to says.
If you use a Bosch or it's got a Bosch in there already, it will not. the Bosch ones are thicker than the NTK ones.
If you are dealing with a Bosch sensor, you'll need to use a 7/8" wrench from above to tighten/loosen it.
If you use a Bosch or it's got a Bosch in there already, it will not. the Bosch ones are thicker than the NTK ones.
If you are dealing with a Bosch sensor, you'll need to use a 7/8" wrench from above to tighten/loosen it.
Re: Code P1131 - 02/19/04 10:52 PM
The O2 sensor I have is "Standard Motor Products, Inc."....? I'm going to go outside right now and look and see if I can see what I'm supposed to be doing. This should be good.
Re: Code P1131 - 02/19/04 11:00 PM
Last time I bought a standard motor products sensor it was an NTK sensor. The part that the wires go into is pretty skinny, maybe 3/8" diameter.
Re: Code P1131 - 02/19/04 11:01 PM
it can be done without removing the coil pack! It really depends how skinny your wrists are. I am a mechanic at a ford dealership, I got tired of taking off the coil pack, use a long 22mm wrench, or a 7/8 standard, an 02 socket also works. Good luck, oh you can rest assured its the 02. Good luck.
Re: Code P1131 - 02/19/04 11:02 PM
I think they sold me the wrong one? I unhooked a couple of the ones outside to see what the connector piece looked like, and none looked like this. The ones on the car had two prongs/holes for the O2 sensor to connect. The one I have has 4 smaller prongs on the O2 sensor that should plug into 4 smaller holes. Is this wrong? Kinda pissed I spent money on this if it is. If this is wrong, does anyone have the part number for the ones that are right? I'll go get it from Autozone right now.
Re: Code P1131 - 02/20/04 12:14 AM
If you give me a few minutes i can look it up on fmcdealer.com. I can probably get the part # off there.
Re: Code P1131 - 02/20/04 12:27 AM
Well I found the part, but not the part #, sorry. If you dont find it I will be able to get it to you first thing in the morning when I get to work.
Re: Code P1131 - 02/20/04 03:42 AM
The one for the Contour's upstream sensors should be a square plug with 4 male pins on the oxygen sensor side.
The downstream sensors should be a round plug, with 4 male pins on the oxygen sensor side.
Make sure you're not accidentally looking at the downstream sensor connectors.
You want to replace the upstream sensor.
SMP has a catalog at http://www.smpcorp.com -- check the part # there.
The downstream sensors should be a round plug, with 4 male pins on the oxygen sensor side.
Make sure you're not accidentally looking at the downstream sensor connectors.
You want to replace the upstream sensor.
SMP has a catalog at http://www.smpcorp.com -- check the part # there.
Re: Code P1131 - 02/20/04 02:44 PM
I found the Bosch part number, but I think the sensor I have may be right then. It does have 4 male ends, so I'm guessing I was looking at the downstream sensor. I was looking at the one just to the right of the coil pack. So I'm guessing thats not it, right?
Re: Code P1131 - 02/20/04 02:59 PM
If it's the one behind the coil pack then it is the right sensor but you cannot see the connector without removing the coil pack--it is attached to the hard plastic wiring harness "conduit" on the back of the engine.
Ehh, another way to know is that the upstream connectors are BLACK. The downstream ones are white or green, as I recall.
Or check the front of the engine right near the dipstick, you'll see an oxygen sensor connector plugged in there which leads to an oxygen sensor right next to the oil filter.
Ehh, another way to know is that the upstream connectors are BLACK. The downstream ones are white or green, as I recall.
Or check the front of the engine right near the dipstick, you'll see an oxygen sensor connector plugged in there which leads to an oxygen sensor right next to the oil filter.
Re: Code P1131 - 02/20/04 05:48 PM
I'm in the process of changing that O2 sensor right now. What a complete PITA to get out. If that plastic conduit wasn't there, it would be easy. I had to take a break before I took a lump hammer to the whole engine. 
Re: Code P1131 - 02/20/04 06:31 PM
Getting it OUT wasn't the problem when I did it. Getting it IN was.
I couldn't get it started from the top, so I had to crawl under the car and get started from the bottom. You know how much room there is to get your hand/arm up in there? Not much. Fortunately, I'm pretty thin. If I were any bigger, forget it. I wouldn't have been able to complete the job.
After I got it tightened from the bottom and tried to put the oxygen sensor socket on it is when I realized that it won't fit over a Bosch sensor.
So I had to go and get a 7/8" wrench from Sears to finish the job.
The plastic conduit can be moved (slightly) out of the way by removing the two bolts holding it down.
I did NOT have to move the plastic conduit when I did this on a '95 V6 Contour but the "vapor management valve" didn't exist on that car and so wasn't in the way. What a dum*** place to put that thing, anyway. There's room further to the left, near the computer, where the ignition module ISN'T on a 96+ car.
I couldn't get it started from the top, so I had to crawl under the car and get started from the bottom. You know how much room there is to get your hand/arm up in there? Not much. Fortunately, I'm pretty thin. If I were any bigger, forget it. I wouldn't have been able to complete the job.
After I got it tightened from the bottom and tried to put the oxygen sensor socket on it is when I realized that it won't fit over a Bosch sensor.
So I had to go and get a 7/8" wrench from Sears to finish the job.
The plastic conduit can be moved (slightly) out of the way by removing the two bolts holding it down.
I did NOT have to move the plastic conduit when I did this on a '95 V6 Contour but the "vapor management valve" didn't exist on that car and so wasn't in the way. What a dum*** place to put that thing, anyway. There's room further to the left, near the computer, where the ignition module ISN'T on a 96+ car.
Re: Code P1131 - 02/20/04 07:47 PM
Thanks ...
I moved the conduit as best I could when I started the work but unfortunately, I still cant get the sensor out. I have it loose but just cant get it all the way out. I thought I could get it done with a 7/8" crowfoot on a 3/8" ratchet but the arm isn't long enough. My hands are too big to fit down there in the gap either. To give you an idea, I cant even get at the rear clips on the airbox.
So I had to walk to Home Depot and thankfully they had a 7/8" wrench thats a little longer than the ratchet.
Here goes nothing !!
I moved the conduit as best I could when I started the work but unfortunately, I still cant get the sensor out. I have it loose but just cant get it all the way out. I thought I could get it done with a 7/8" crowfoot on a 3/8" ratchet but the arm isn't long enough. My hands are too big to fit down there in the gap either. To give you an idea, I cant even get at the rear clips on the airbox.
So I had to walk to Home Depot and thankfully they had a 7/8" wrench thats a little longer than the ratchet.
Here goes nothing !!