Replacing early model ECU w/ tune-compatible version

  #1  
Old 02-13-2019, 04:57 PM
Registered User
Thread Starter
Join Date: Feb 2019
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
5AT, Manzo single-exit catback
Replacing early model ECU w/ tune-compatible version

I'm in a 2003 G35 Sedan with the automatic transmission. o/

I've recently been doing some work on it here and there, but if I want to go any further I need a tune. I checked my service manual and serial number and it seems like I'm running the older, incompatible ECU with the early pinout that can't be flashed or tuned by any of the popular programs. At the moment, I plan to swap my engine harness out for a later model G35's harness and drop in the newer ECU. Anyone see any issues with this plan? The transmission controller is entirely separate and based on what I've seen in the manual, the ECUs don't differ between manual or automatic (or even between G35 and 350z!). If I did end up dropping in a new harness, say from an 04 G35 Sedan, along with that ECU, would I have any major issues that you guys might know about? Would I be able to start up immediately or will I need to do all this at a shop/dealership that can flash some kind of default stuff on to get me going?

None of this is really my specialty, I've just been doing a bit of reading lately so I probably have big holes in my knowledge. If anyone can help me out here or bring me up to speed on why the old ECU isn't tuneable, I'd really appreciate it!
 
  #2  
Old 02-13-2019, 05:09 PM
cleric670@gmail's Avatar
BANNED!!!
Join Date: May 2017
Location: Washington State
Posts: 6,973
Received 816 Likes on 750 Posts
Coupe 6MT Premium RAS
You will also need to program the ECM to accept the BCM and TCM, this can be done with the Nissan Datascan 2 software on a PC. Check out this thread, the BCM decoder link might still work and save you a few bucks.

https://g35driver.com/forums/g35-cou...tool-nats.html

I'm also pretty sure the ECM is transmission specific, maybe it was AWD/RWD specific, can't exactly remember.

They are also specific based on iKey or regular key.

And you will be switching to dual electric fans instead of 1 electric / 1 mechanical.

I think the best thing to do would be find someone with a 2003 coupe with the newer ECM and get the part numbers off the ECM/TCM/BCM/IPDM.

Unless you have some kind of attachment to that exact vehicle it would be a LOT easier (better) to just buy a newer version that is tuneable.
 
  #3  
Old 02-13-2019, 06:56 PM
Registered User
Thread Starter
Join Date: Feb 2019
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
5AT, Manzo single-exit catback
Originally Posted by [email protected] View Post
You will also need to program the ECM to accept the BCM and TCM, this can be done with the Nissan Datascan 2 software on a PC. Check out this thread, the BCM decoder link might still work and save you a few bucks.

https://g35driver.com/forums/g35-cou...tool-nats.html

I'm also pretty sure the ECM is transmission specific, maybe it was AWD/RWD specific, can't exactly remember.

They are also specific based on iKey or regular key.

And you will be switching to dual electric fans instead of 1 electric / 1 mechanical.

I think the best thing to do would be find someone with a 2003 coupe with the newer ECM and get the part numbers off the ECM/TCM/BCM/IPDM.

Unless you have some kind of attachment to that exact vehicle it would be a LOT easier (better) to just buy a newer version that is tuneable.
Ah damn. I have a bit of attachment to it, it's my first car. If that's the case I think I'll just leave it untuned for a while until I can settle my mind on an option that I don't second guess. Is there any particular reason why these ECUs can't be tuned? Is it that the software isn't set up to interface with them since they aren't the most common version of the unit (only on early 03 models), or is it just that it can't be flashed at all for some technical reason?

Also: I'm getting my info about the manual/automatic ECUs being the same from the manual, but that's all theory. There could be minor differences that would prevent them from being swapped out easily. All I saw was "Type 1" and "Type 2", and one of them was only for early automatic models and the other was for all automatics after a certain serial number and all manuals.

Anyway, my new plan at the moment is probably going to be a Haltech Elite 750. I'm gonna start researching its compatibility, but if it's able to work fine with what I'm running it's ideal for me since I have a friend with the software who knows how to use it.
 

Last edited by cfitz22; 02-13-2019 at 07:04 PM.
  #4  
Old 02-14-2019, 11:22 AM
seymore4's Avatar
Premier Member
iTrader: (112)
Join Date: Mar 2009
Location: West coast
Posts: 4,674
Received 315 Likes on 252 Posts
I would not trust the manual; take a look at the physical ECU and confirm which version you have. If it looks like the silver box on top then you are correct it is not tuneable via Uprev

.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
danfrompa
V36 Engine, Exhaust, Drivetrain & FI
23
02-01-2016 12:47 PM
03BaseSedan
Tuner & Dyno
124
12-21-2010 01:55 AM
SPCK
Buying, Selling & Leasing Discussion
13
09-18-2007 03:00 PM
tig488
Archived Sales
8
12-27-2006 12:16 AM
ATL_Red_G35
The G-Spot
12
05-17-2006 05:17 PM


Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: Replacing early model ECU w/ tune-compatible version


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: