O2 sensors codes after ECU swap. Need help with this!

[spdracr]

So thanks to M-rod for getting me specific diagrams so I can confirm my ecu swap. Everything checks out according to those diagrams. My oxygen sensors are properly wired to their corresponding heater and grounds. So what else could be causing my codes then??

im open to any suggestions that would possibly help me fix this.

i have replaced both O2 sensors in hopes to make those codes go away.

didnt have those codes when i was tuned on the auto ecu

codes are P0135 and P0141 which are both for O2 sensors heater circuit

[Galantman03]

Do you have Power at the o2 connector for the heater.

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[spdracr]

Do you have Power at the o2 connector for the heater.

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i havent checked honestly, i guess my question are these codes both for the front sensor or is each code for each sensor ?

so you want me to check for voltage at the heater wire for each sensor on the ecu side ?

[Ivory8g]

Those two codes are the first o2 sensor. Basically what is happening is it is taking too long to heat up and the ecu realizes this and throws a code. Check the grounds for the engine harness.
-Ground 1- Engine firewall to throttle body cable plate, pull the grounding cable and take a brillo pad to the connecting surfaces. Make sure the metal parts that touch are shiny.
-Ground 2- Then one by the thermostat housing
-Ground 3- I believe there is one on the tranny as well right where the uicp passes over the tranny (didnt mark that one)

[spdracr]

Those two codes are the first o2 sensor. Basically what is happening is it is taking too long to heat up and the ecu realizes this and throws a code. Check the grounds for the engine harness.
-Ground 1- Engine firewall to throttle body cable plate, pull the grounding cable and take a brillo pad to the connecting surfaces. Make sure the metal parts that touch are shiny.
-Ground 2- Then one by the thermostat housing
-Ground 3- I believe there is one on the tranny as well right where the uicp passes over the tranny (didnt mark that one)

I replaced that ground between the intake manifold and the firewall with an 8ga ground and some copper terminals. I have also added like 6 more grounds to the engine in varies locations. I will check the ground by the thermostat housing and see if it's loose or not.

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[Ivory8g]

make sure the connectors are metal to metal behind the screws on the t-stat housing

[spdracr]

My tune was causing my codes. New tune should fix my issue. Keeping my fingers crossed.

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[Silvertune]

Did you use a jumper harness or mod the stock harness?

[spdracr]

Made my own conversion harness.

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[Silvertune]

Those pics you showed me are impressive. Such craftiness I have not observed on these forums in a long time.

[spdracr]

Thanks Justin. I tried to clean it up a bit but I didn't have enough slack in the wires.

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[finald8ta]

so your saying its all in the tune this helps me out alot with my buddies 3g. Keep me posted sdracr

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[spdracr]

Got my tune. I'm sitting in my car right now flashing it. Will run it and log it and send it back to the tuner to disable the cel and tweak it for me a bit.

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[Ivory8g]

so your saying its all in the tune this helps me out alot with my buddies 3g. Keep me posted sdracr

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Just so it's clear as some people know I tuned this car at one point. I tuned it on the auto pcm. Never had any O2 codes. Didn't touch it when the ecu was swapped.

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[spdracr]

I flashed tephra V7. Only codes pending are the same o2 codes again. He's gonna check the tune and see what's going on. If it's my harness then I'm going over it next week with a voltmeter to see what's wrong.

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[spdracr]

Just so it's clear as some people know I tuned this car at one point. I tuned it on the auto pcm. Never had any O2 codes. Didn't touch it when the ecu was swapped.

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i believe at one point i have mentioned that i was code free when you tuned me on auto ecu.


my tuner says both o2 sensors are working fine after he looked at my logs. he will take a look again and see what he can do. tomorrow im installing the evo maf and evo map and gonna log it again and he is gonna tweak few things for me. but for now my afr at idle is in the mid 14s which is not a bad start

[Ivory8g]

Yep I remember our conversations. Just stating before anyone went down that path

[spdracr]

No I meant I have mentioned here on one of the threads.

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[spdracr]

The codes were a problem of ecu compatibility. Eclipse ecu with Evo rom. Switched to Evo ecu and they're gone .