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Manual Swapped!!
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Discussion Starter · #1 ·
If you have read my build thread you know that I've been haveing an issue with codes p0135 and p0141 heater circuit malfunction front and rear.

I am completely lost as to what to do now. Here is the background:

2003 GS auto I swapped to a manual. I then had Wanted a GT make an auto to manual conversion harness useing the pinout diagrams in the FSM. He checked the continuity as he made it. When I recieved it I verified the pinouts were good to go.

I used a 2002 GS ECU with a stock 2001 GS ROM. When I plugged it in is when these codes came. I searched the forums and the problem threads that do have the issue solved is due to a wiring issue and/or bad o2 sensor. I checked the wiring and replaced the front, still have the problem.

Here is what I've done:
1) I checked the pinout of the o2 sensor heater circuits, they were in the right spots
2) I verified the continuity of the 2 o2 heater circuits, it was good
3) I swapped the 2 pins just in case the pinout was wrong, it caused more codes so I swapped it back
4) I checked the wiring of the o2 sensor at the ecu, at the OEM auto harness and at the front o2 sensor itself, they were good to go

Here is where I just tried to diagnose the front only as the rear is a PITA

6) I cleaned the plug
7) I replaced the front sensor

I STILL HAVE THE STUPID ISSUE!!

I really don't know what to do now, could it be a difference between 02 and 03 in either the ECU or the ROM? It can't be a bad ECU as there would be more issues right? PaleHorse checked the ROM and said nothing is out of the ordinary with the ROM.

Thanks for the help guys, I'm just completely lost.
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #3 ·
Drove to the movies tonight and my cel came on which is different in that it usually doesn't come on with the p0135 and p0141 until I start the car, turn it off then turn it on again. With this cel I have yet to do that cycle. I came home and checked it with Evoscan and it came up with p0134 heater sensor front no activity.

I replaced the front o2 sensor with a cheap Bosch one for the sake of diagnostics. This new code popped up :facepalm: I will be putting the NGK one back in tomorrow as it was not the problem. I ill also be trying the auto ecu to see what's up.

I also stand corrected with 135 and 141 they are only a circuit fault, whereas 134 is no activity for the front. I don't know the rear as it didn't pop up, reassuring me that now its the Bosch sensor.
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #4 ·
Did some work:

Put the 2003 GS auto ECU in, the o2 codes went away. All I had were the 5 codes that say WTF happened to the trans. I drove it around and there were no o2 codes even after cycleing it on and off a few times.

So I put the NGK o2 sensor back in and p0134 is gone. I still have p0135 and p0141. Due to this I have to assume that there is a difference between the way the 00-02 ECU/ROM and 03+ ECU/ROM communicate with the cars o2 sensors/computer system. One of you tuner people please step in and let me know if I can edit this or need an 03+ ROM and/or ECU
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #6 ·
An 03 to 05 would be great lol. My car is an 03 and I have an 02 ECU with an 01 ROM I think that is the problem
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #9 ·
So today I got a 2003 GS manual ROM with the Immob deleted. I flash it to my ECU, and the car will not start. It cranks but does not turn over.

There has to be a difference in the way the ECU's work with the rest of the electrical system between the 2 models. Yes the pinouts are the same but there has to be a diffeence. If there was not my 2002 ECU would accept the 2003 bone stock ROM with no issues.

I had to put the 2001 ROM back on and the car started right up, no issue. But the CEL is still there for the same 2 codes. I need a 2003+ ECU.

I believe I am the first to encounter this problem and will follow it through. If Im not please let me know.
 

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Premium Member
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8,831 Posts
There is a 2003 GS Manual trans at the yards near me if you need me to pull the ECU let me know. im not sure how much it will be though.
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #12 ·
So wtf? I finally got an 03 GS ECU (thanks Eric) I plug it in, and the car cranks and cranks but won't turn over. I tried 3 different "stock" 03 GS ROM's w/out immob's and the same thing. I flashed the 01 ROM on the new ECU and it turns over and run but it still throws the codes.

Can someone with some experience please help?
 

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124 Posts
from your earlier post continuity doesn't mean good connection it means there is at least some connection.....you can have continuity in a 20 strand wire with only one strand not broken.....you need the check resistance.....under 2 ohms is acceptable for most not all Mitsubishi circuits..
 

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Manual Swapped!!
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5,977 Posts
Discussion Starter · #14 ·
I am still working on this. I'm just going to replace those strands and see what that does. I'm still lost. The worst part is that the codes are a circuit fault, not a malfunction, not no signal but a fault. It still works fine but I won't pass inspection. The pinouts and internal hardware of the 2000-2005 auto and manual ecu's are the same so it's not a difference there.
 
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