Hello all,

Longtime follower, first time poster here.

I have a 2001 Civic EX that had a stock motor. A family member borrowed the car and blew a hole in the block (don't ask me how). So I had it towed to my uncle's shop and I asked him to swap the engine. He found me a cheap LX engine and dropped it in.

The car fires up just fine, but since it still has the stock EX ECU, I get the P1259 engine code error which is for the VTEC (which is now missing).

So my question is, how can I fix this error? Do I need an LX ECU? I've read that if I do get an LX ECU, it may not function very well with the transmission, since the transmission is from the EX...? I also read that I could possibly just add the EX head to the LX engine and this may work...?

I've tried searching online, but most people swap their engines from an LX to an EX, and never the other way around.

I have no idea. Please help.

 

you swapped your vtec out for no vtec? You messed up man. Just swap the ex back in and you'll be good. I would say if u cant to maybe try a lx ecu first, then if that doesnt work try an lx trans computer.

 

Swap an EX head for the LX head or get a whole EX engine, whichever is cheaper.

Nationwide salvage listings: http://www.car-part.com/

 

i would say swap to a ex head. probally the easiest way

 

Thanks everybody for the replies. I have another headache to deal with, but I'll start a new thread...

I'm going to look for an LX ECU and hope that works.

 

Say goodbye to a working moonroof- and any other accessories the EX has but, the LX doesn't. Just sayin...

 

That's not how that works lol. You're multiplex control unit controls all of you accessories. I had an ex car with an lx motor, replaced the ecu worked perfectly, then I replaced the head with an EX head and put the original ecu back, worked even better then, accessories always worked with any combination of motor/ecu.

Replace the computer with an lx computer 37820 PLM A53
*IF* the car does not drive properly, replace the transmission computer.

*Or* replace the head with and ex head and keep the current setup.

 

I got the EX head back from my uncle (he still had it at his shop) so I'm going to swap it and I won't have to mess with the ECU after all. I got to thinking about it some more, and I was afraid the ABS light might stay on forever if I swapped the ecu for an LX one. Maugutus, did you have any trouble with your ABS during the time you were running the LX ecu? By the way, thanks for that info! It's still very useful for future reference.

 

If I remember correctly the ABS is tied into the ECU, but it has a separate control unit and LX cars do not have ABS. I'm pretty sure my ABS light wasn't on when I had the LX ECU in the EX. The only way to really avoid headaches though is to put that ex head back on it, polish it a bit, do a valve job and all that machining and slap it back on.

Is the ABS light on now? I would like to research this further. Thinking I might swap out my ECU and check.

 

Yes, the ABS light is on now.

Does anyone know if the ABS light will stay on if I swap my EX ECU for an LX ECU in this car?? If so, I may just avoid the headache of swapping the head..

 

UPDATE:

Big Thanks to Maugutus! I swapped the ECU and the car runs just fine! I've got just a couple of minor issues to go, and I'll be able to pass inspection soon.

Got another question:
Now that I have an LX engine, I'm getting errors on the O2 sensors. Is this because the EX engine O2 sensors are different from the LX engine sensors?