Background-
Bought '10 TL Tech from an auction last year. The car flooded and the engine was hydro-locked. All interior features/accessories work fine. From Nav to seats and the IP does not have any MILs. Also, slight flood smell (will replace carpet) but it's clean and no rust so I think it was minor.

What's been done:
Not knowing any better, I bought a 2012 3.5 I noticed the harness was a little different so I used the original 2010 harness.

Replaced timing belt and water pump.
No fuel- replaced the sending unit
No BCM communication from ECU - replaced ECU
-- Rewrote the VIN and reset the immo since the green key flashed (had to but a capable scanner since the dealer wanted $1,150 for the ECU plus $300+ labor with no guarantees)

Currently:
Still get the BCM code but I was not able to find a BCM module (Using DYIAllData)
The car just cranks but does not start.

I just ordered a 2012 ECU ($115 from salvage yard). Should be here in a few days.

What I'm planning:
The plan is to replace the wiring harness back to the 2012 and use the 2012 ECU and reprogram my keys to it.

My question (HELP!!):
Has anyone been able to replace the 2010 J35 with a 2012 J35 successfully? If so, please share your insight.

 

interesting...it's the same motor.

silly question; is the ECU fuse under the hood blown?

 

Not a silly question. It's fine.

 

cuz one day; I was messing with the car....and I had gotten the green key flash...(immobilizer)...had a friend use the HDS and Honda software to reset the immobilizer, however my car wouldnt start.

after a few days of troubleshooting, my ECU fuse was blown. preventing the car from starting.

 

You got my hopes up but I just checked all of the fuses under the hood and they're all good.

I was reading/comparing parts between the 2010 and the 2012. I saw that the torque converter was different. So, I saw that the transmissions are different (5 spd and 6 spd.) It may be that after it starts, I'll have to change the transmission also. I checked and can get a used one for about $300. The engine wiring harness seems to have all of the trainny wires/plugs so that should be fine (I hope).

In the next couple of days, I'll remove the '10 wiring harness and compare each plug to the '12. I'll note the any color differences or wire locations just so I'll know what components may be different and may help if the car does not run with the '12 computer. So far, the only part that I've seen is different is the flex plate,torque converter and trainny.

justnspace, I appreciate your help. Wish I could share some of this fun :-)

 

I'm going back to the basics. After comparing the pinout for the 2010 and the 20112, the differences are very minor and none that should keen the car from running.

The differences noted from 2010 point of view:
Connector A: Pin #44

Connector B: Pins #43 and #44 on 2012 relate to trainny

Connector C: Pin #9 on '10 goes to solenoid C, '12 goes to solenoid D
Pin #23, N/A on '10, O2 rear bank 2 on '12
Pin #36 N/A on '10, O2 rear bank 1 on '12
Pin #31 N/A on '10, 6th clutch on '12
Pin #35 N/A on '10, OPPL line pressure

Any suggestions are welcomed!!

I'm attaching the pdf's for both years in case anyone else needs the info.

 

I had to do two uploads.

 

2012 TL FWD pinout

 

Likely that the immobilizer is preventing the car from starting.