Multiple o2 codes, p0135, p0131, p0141
05-08-2016
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Multiple o2 codes, p0135, p0131, p0141
As I've searched thru this forum I've come across many post about different oxygen sensor codes triggering the check engine light. It seems many of these post kind of end abruptly with no final resolution, or the member posting never comes back and says "hey I fixed it for good and here's how!" so I'm kind of hoping to get some feedback and advice on my issue. Id like to try and make a very long story short, although that may be hard to do with this project car that I'm working on
Car history. 2001 Honda Civic LX 1.7 liter standard transmission. Bought used with bad motor and CEL on the dash. Bought it with a bad motor because I had a 2005 Honda Civic HX 1.7 liter from a car that my daughter had rolled over. Hers was a low mile motor and ran great prior to her accident.
When i got the used 2001 car home i never bothered scanning the system for codes. I wasn't really concerned about it at that time thinking that it was probably something to do with the way the young man treated the car. I was hell bent on just getting the newer motor in.
The engine swap went great. We Installed new timing belt, water pump, tensioner, seals oil pan gasket and all the goodies before we put the 2005 engine into this car. Got everything together and the car fired right up and ran like a top. But the check engine light was still on. I figured I could scan it and clear it and whatever was happening with the old motor would be gone and hopefully everything will be great with the new motor. I hooked my scanner up to the data link connector and I couldn't power up my scanner. Tried that multiple times and couldn't figure out what was going on so I borrowed my friend's scanner and had the same issue.
After some diagnostic work I found out that I had a massive amount of wiring under the dash that had been melted.it looked like it started behind the radio and headed to the multiplex. The only saving grace to that discovery was that I had my daughters wrecked car to scavenge wire from. I couldn't use her complete wiring harness because there were differences between the two cars. So we cut out as much as we could. We pulled the dash off the 01 and rewired everything that we could find melted. After all that, i still could not link my scanner with the ECM.
I wasn't sure exactly where to go next because I stated thinking maybe I had a bad ECM. as luck has it, I work for a pretty large salvage yard so I grabbed a used ECM for my same make and model Honda as well as the ignition cylinder and key. The car would start and run fine, check engine light was still on, and I still couldn't communicate with the new ECM. That's when I realized I had no power to the data link connector. So after doing some electrical diagram research I realized it get power from the fuse box under the hood and I ran a direct line from the number 9 fuse area to the data link connector and presto I was finally able to communicate with the ECM and retrieve codes.
I pulled P0135. I was able to clear the code but it would come back shortly after. There was a time period where I would clear the code and drive for 40 or 50 miles and the light would be off. I would come home and park the car for awhile then I'd start the i up and light would have immediately come on. After a lot of reading different posts on this forum and doing some wiring diagram investigation I checked for power and ground at the o2 plug and realized I had no ground from the ECM to the o2. I tested the ground wire at the ECM and there was ground coming out, but not getting to the O2 plug so I determined that I had a wire somewhere in between that we must have missed.
I ran a temporary spliced wire from the ECM to that plug. And that seemed to clear up the p0135. But no sooner did I "think" I had it repaired, a code for p0141 came up. In all the prior times I scanned, that code was neve present. Im sure i will have a similar wire issue with that.
There is one thing that caught my attention today after reading some of these post that I didn't realize. During the engine swap I used the manifold from the 2005 HX on the 2001 LX. And it appears that the the O2 sensors from the 2005 very well may be different from the ones in the 2001. Another starting point
See I told you it was a short story
Car history. 2001 Honda Civic LX 1.7 liter standard transmission. Bought used with bad motor and CEL on the dash. Bought it with a bad motor because I had a 2005 Honda Civic HX 1.7 liter from a car that my daughter had rolled over. Hers was a low mile motor and ran great prior to her accident.
When i got the used 2001 car home i never bothered scanning the system for codes. I wasn't really concerned about it at that time thinking that it was probably something to do with the way the young man treated the car. I was hell bent on just getting the newer motor in.
The engine swap went great. We Installed new timing belt, water pump, tensioner, seals oil pan gasket and all the goodies before we put the 2005 engine into this car. Got everything together and the car fired right up and ran like a top. But the check engine light was still on. I figured I could scan it and clear it and whatever was happening with the old motor would be gone and hopefully everything will be great with the new motor. I hooked my scanner up to the data link connector and I couldn't power up my scanner. Tried that multiple times and couldn't figure out what was going on so I borrowed my friend's scanner and had the same issue.
After some diagnostic work I found out that I had a massive amount of wiring under the dash that had been melted.it looked like it started behind the radio and headed to the multiplex. The only saving grace to that discovery was that I had my daughters wrecked car to scavenge wire from. I couldn't use her complete wiring harness because there were differences between the two cars. So we cut out as much as we could. We pulled the dash off the 01 and rewired everything that we could find melted. After all that, i still could not link my scanner with the ECM.
I wasn't sure exactly where to go next because I stated thinking maybe I had a bad ECM. as luck has it, I work for a pretty large salvage yard so I grabbed a used ECM for my same make and model Honda as well as the ignition cylinder and key. The car would start and run fine, check engine light was still on, and I still couldn't communicate with the new ECM. That's when I realized I had no power to the data link connector. So after doing some electrical diagram research I realized it get power from the fuse box under the hood and I ran a direct line from the number 9 fuse area to the data link connector and presto I was finally able to communicate with the ECM and retrieve codes.
I pulled P0135. I was able to clear the code but it would come back shortly after. There was a time period where I would clear the code and drive for 40 or 50 miles and the light would be off. I would come home and park the car for awhile then I'd start the i up and light would have immediately come on. After a lot of reading different posts on this forum and doing some wiring diagram investigation I checked for power and ground at the o2 plug and realized I had no ground from the ECM to the o2. I tested the ground wire at the ECM and there was ground coming out, but not getting to the O2 plug so I determined that I had a wire somewhere in between that we must have missed.
I ran a temporary spliced wire from the ECM to that plug. And that seemed to clear up the p0135. But no sooner did I "think" I had it repaired, a code for p0141 came up. In all the prior times I scanned, that code was neve present. Im sure i will have a similar wire issue with that.
There is one thing that caught my attention today after reading some of these post that I didn't realize. During the engine swap I used the manifold from the 2005 HX on the 2001 LX. And it appears that the the O2 sensors from the 2005 very well may be different from the ones in the 2001. Another starting point
See I told you it was a short story
05-08-2016
#2
If you think a good mechanic is expensive, try hiring a bad one
Re: Multiple o2 codes, p0135, p0131, p0141
I work for a pretty large salvage yard so I grabbed a used ECM for my same make and model Honda
What's the part number on the PCM?
There is one thing that caught my attention today after reading some of these post that I didn't realize. During the engine swap I used the manifold from the 2005 HX on the 2001 LX. And it appears that the the O2 sensors from the 2005 very well may be different from the ones in the 2001. Another starting point
You are probably going to need to install a primary O2 sensor for an 01-03 Civic first.
Denso brand or NTK brand sensor, whichever brand the original engine used.
No Bosch, Wells, or other cheap crap sensors.
I couldn't use her complete wiring harness because there were differences between the two cars.
05-08-2016
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What specific car did it come from?
What's the part numberThe ECM came from another 2001 Civic LX w/standard trans. Identical to the one I have. I don't have the part number available at the moment, but it was a match as far as our interchange numbers go.
[/QUOTE]Correct, the primary sensor in 04-05 cars is not an O2 sensor.
You are probably going to need to install a primary O2 sensor for an 01-03 Civic first.
Denso brand or NTK brand sensor, whichever brand the original engine used.
No Bosch, Wells, or other cheap crap sensors.
There are large differences between the years, at least one difference is in how the primary sensor receives 12v power.[/QUOTE]
I ended up taking the upstream o2 from the original motor (2001) and put that in. The p0131 & p0135 have cleared and stayed gone. This was after i ran a temporary ground from the PCM (black/white wire). If I disconnect that temporary ground I can trigger the CEL and those codes every time. I must have a break in a wire in between. pcm And O2 connector.
I test drove the car for awhile this morning trying to get the monitor's to set. The P0135 and p0131 we're gone. I thought I was on my way. All the monitors set except the EVAP. Then just when I thought things were looking up. The check engine light came on again. I scanned and found Code PO141 again. What is odd is that PO141 never comes up if the other two are present. So I took the original Downstream (bottom of the cat) sensor from the old engine and put it into this one and cleard the codes. I test drove the car for a short distance and the code came back within a short time. So now I'm going to have to go do the same type of test that i did for the downstream that I did on the upstream. I suspect that wherever the broken/bad wire was for the Upstream I probably have a similar situation for the downstream
What's the part numberThe ECM came from another 2001 Civic LX w/standard trans. Identical to the one I have. I don't have the part number available at the moment, but it was a match as far as our interchange numbers go.
[/QUOTE]Correct, the primary sensor in 04-05 cars is not an O2 sensor.
You are probably going to need to install a primary O2 sensor for an 01-03 Civic first.
Denso brand or NTK brand sensor, whichever brand the original engine used.
No Bosch, Wells, or other cheap crap sensors.
There are large differences between the years, at least one difference is in how the primary sensor receives 12v power.[/QUOTE]
I ended up taking the upstream o2 from the original motor (2001) and put that in. The p0131 & p0135 have cleared and stayed gone. This was after i ran a temporary ground from the PCM (black/white wire). If I disconnect that temporary ground I can trigger the CEL and those codes every time. I must have a break in a wire in between. pcm And O2 connector.
I test drove the car for awhile this morning trying to get the monitor's to set. The P0135 and p0131 we're gone. I thought I was on my way. All the monitors set except the EVAP. Then just when I thought things were looking up. The check engine light came on again. I scanned and found Code PO141 again. What is odd is that PO141 never comes up if the other two are present. So I took the original Downstream (bottom of the cat) sensor from the old engine and put it into this one and cleard the codes. I test drove the car for a short distance and the code came back within a short time. So now I'm going to have to go do the same type of test that i did for the downstream that I did on the upstream. I suspect that wherever the broken/bad wire was for the Upstream I probably have a similar situation for the downstream
05-12-2016
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issue resolved:
end result, i must have a bad/broke ground wire(s) in the engine wire harness from ECM to o2 sensor plug(s). This is hardly a surprise with all the wiring issues i inherited with this car. I replaced the sensors with correct units from the 2001 LX. I had ground coming out of ECM at pin 1 & pin 14 for both o2 sensors but it wasn't reading ground at plug. I t-tapped both blk/wht ground wires at the ECM and ran new ground wires to o2 plugs, issue resolved. CEL is off, all monitors set, and state inspection now complete. just in case any one was interested
end result, i must have a bad/broke ground wire(s) in the engine wire harness from ECM to o2 sensor plug(s). This is hardly a surprise with all the wiring issues i inherited with this car. I replaced the sensors with correct units from the 2001 LX. I had ground coming out of ECM at pin 1 & pin 14 for both o2 sensors but it wasn't reading ground at plug. I t-tapped both blk/wht ground wires at the ECM and ran new ground wires to o2 plugs, issue resolved. CEL is off, all monitors set, and state inspection now complete. just in case any one was interested
