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Hello,

About a week ago I swapped out my 02' Civic DX's d17a1 for another d17a1.

The d17a1 I put in is out of a 04' Civic SE and had very low mileage vs the one I had. Both are MT.

I had put the 04' ECU to match the engine, however the immobilizer did not like that and thus the car would turn over but not start. So... I put the 02' ECU back in and it seems to run find, except for the CEL that is on. Which leads me to believe that it is causing my CEL issue, but I don't know exactly why.

My question is; would the ECU be causing the CEL due to it not matching the the engine VIN or is there possibly a sensor issue or is there another more likely cause? I realize that plugging in an OBD tool could be a big help, but at the moment I do not have access to one.

Also, is a honda dealership able to reprogram the 04' ECU to my chipped key?

Any helpful input would be much appreciated.

Thanks

 
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if you have an autozone parts store near you they will usually check the engine code for free. you may have just missed a connector or something simple like that. not sure why you would be switching your ecu out though? is there something wrong with your original ecu? You are not required to install a new ecu when you change the engine. the new engine should run just fine w/ your original ecu unless this new engine has a different operating system. in that case i would assume you would have some wiring to do?

 
Rep Power: 219

The immobilizer will not cause your CEL. You had to have missed something. I just replaced my a2 and I just kept the old ECU and it worked fine. There has to be something you missed.

 
Rep Power: 297

It could be a million things. I would get the code checked and go from there. Also re-inspect your work. You could have broken a wire on a connector when changing the motor. Happen to me one time.

But my car is on its 4th motor now. Damn boost.

 
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for one, i would say the o2 sensor is the cause, the 01 to 03 d17s used a narrowband o2 sensor while the 04-05 used a wideband sensor.

 
Rep Power: 297

Damn totally fogot about that. Good call. Yup. That would be your problem for sure. Change out your O2 with the old one. Good call HLC

 
Rep Power: 219

WOW! I completely forgot about that too!!!

 
Rep Power: 313

That's gonna cost you some cash to replace. The wideband sensors are hundreds of dollars

 
Rep Power: 297

He should have the old one from the old motor. If not pull your rear O2 and put it in the front and buy an O2 simulator for the rear. or you could rock no rear O2 untill you can buy a new narrow band one. Wont hurt anything.

 
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Thanks for all the responses guys. I will double check everything, and I did keep the O2 sensors. Will post my results if I can find the cause. If not, I will have a code reader on the weekend and see what it pulls.