A few questions regarding swapping OS

[Agtronic]

Hey all,

I recently purchased an LS2 motor out of a TBSS to put into my E46 sedan. It came with an E38 ECM and harness from a 2007 Silverado 2500 6.0L. I will be using my E46 ZF 320Z 5-speed manual.

Currently, I'm in the research phase, and have spent about 2 months reading-up about potential issues I may run into. It is my understanding that this ECM is going to be expecting VSS data over CAN BUS. I understand that without the TCM steaming this data, the ECM will default to a 186mph static reading, which in turn causes issues with RPM hang and other throttle control oddities.

If I understand correctly, a solution would be to have the base OS (my terminology may be wrong here) swapped to one that would come on a manual car. I understand that this is not that simple, and not something I could use HP Tuners for, due to certain segments being inaccessible to the tool. I also realize that even with the correct GM flashing tools, one must be careful of which OS the ECM currently has VS the one you want to flash.

My ECM: Service 12597121 / OS 12618278

I found this document that groups together OS numbers which are "known" to be compatible. However, my OS number is not listed. I see there is one that is one digit off, I inserted mine in red on the screen shot below:



I discovered that OS 12617631 (two above where I inserted mine) was used for LS3 Corvette 6-speed, so that would be ideal. I would remap for 6.0L in HP Tuners later. The problem is, I'm making a big assumption that my OS falls under that column, and from the looks of it, they really don't follow any strict serial sequence.

Some questions:

- Is my understanding of what needs to be done correct?
- Is my assumption that my OS number falls in the 2008 ECM column a dangerous one?
- Would it just be easier to order an ECU online, flashed to a 6 speed 'Vette VIN? (I found a few.)
- Any recommendations on someone who can do this in Canada? I'm in the (Montreal area.)


I called a few places, and they told me that flashing to a different VIN was not possible, even with the GM flash tools. I'm thinking they just aren't familiar with this process.

Also, I would like to stick to ordering / shipping within Canada, as I got royally destroyed when ordering HP Tuners from the US. What was supposed to be a $399 device ended up costing almost $1000 CAD after adding UPS brokerage and factoring-in the USD/CAD exchange rape...

Thanks in advance for any insight you may offer. I recognize that many of you have a lot of time under your belts messing with this stuff. It's always appreciated when knowledge is shared.

Best,

[obthomas]

I am no expert, but I have been down this road. I believe you are spot on with the VSS situation and in addition the automatic transmission data also interfaces with torque settings. You absolutely should deal with the transmission disparity. I personally went the Corvette VIN with a manual transmission route. Other than power to the computer and engine coils injectors and sensors I had very little interface to the car so it worked well for me. I had to add a VSS to the car and connected it to the ECM pins 71 and 72. I know nothing of the E46 computer and less about how to convert it to a manual transmission. No matter I think you LS2 needs control from an ECU that is for a manual transmission. Part of the fun for my conversion was getting there. I wish you luck and hope you will get back to us once you are sucessful. Good Luck.

[Alvin]

I'd pick as many components as possible from some OE application. The pedal and throttle body are important to pick from some OEM application together.

If your set on a E38 but need it for a manual.. Vettes and camaro's are an option.

As far as the compatibility. There are certain OS numbers that flat out aren't compatible. I believe they are different on a hardware level even though they are both are marked E38. My sales person is super smart on this and if you need you can reach them at [email protected]. You don't have to buy anything.. I'm sure they will be glad to help.

[mtvainiot]

Service number 12597121 is 2007 ECM. 2008 ECM service number is 12612384. So you can not flash 2008 OS to 2007 ECM. What you can do is use 2007 Corvette manual OS. OS change on E38 ECM can not be done with HP-Tuners. You have to find 2007 manual Corvette VIN and flash ECM with GM SPS/TLC. Easiest way is purchase Corvette VIN programmed ECM from eBay.

[blindsquirrel]

...at which point if you don't have the tools & SPS subscription it's way cheaper to buy a used ECM of the correct service number pre-SPSed to a VIN you supply.

...and if doing that, there is no reason why you have to stick with a 2008 ECM/OS. The 1- or 2-year-only early service numbers can cost a lot more than the most common ones. 12633238 was used from 2010 all the way thru 2017, you just need to pick a manual trans OS from a year that's compatible with that service number.

[Agtronic]

Thanks all for your insight. It's very much appreciated.

I did not realize that there was one service number for each ECM year, but definitely a crucial bit of info.

I'm not dead set on the E38, but I already have a harness with the correct connectors to use with it. I'm trying to be careful on what I spend as I know damn well this is probably going to snowball and I'm not trying to get divorced.

I'm going to hit up a few places, if finding someone to swap the OS proves too difficult (or expensive), I'll simply order a fresh ECU online with the correct OS loaded.

[Alvin]

Just choose ECM/TCM Pedal and throttle body from one OEM example.. Mismatching is where you run into problems.

[blindsquirrel]

Physically, all E38s interchange (the connectors and exteriors are the same). But you can't put a 2007 E38 OS into a '08-'09 E38 or a '09-'10 E38 or a '10-'17 E38, and you can't put a '10-'17 E38 OS into any of the others, etc. There's differences inside with stuff like memory size/addresses and other board-level things. Their compatible TBs/APPs can also change across those years and all the various platforms too (there may be some overlap in some places, but there's no such thing as one TB and one APP that works with all service numbers/all OSes).

[IronBird]

I’m in the same situation as you (2013 E38 from a Silverado mated to a T56). Corvette pedal. The ECM doesn’t receive a valid VSS or clutch signal but it runs and drives pretty well (600hp twin turbo). I would still really like to have the VSS and clutch signals for logging, RPM limiting, etc. Let us know where you end up.

[blindsquirrel]

https://www.ebay.com/sch/i.html?_nkw...tering&_sop=10

1G1Y32DWXD5103335 - 2013 LS3 Corvette, confirmed by SPS to be a manual trans

This is real easy, guys.

[Agtronic]

https://www.ebay.com/sch/i.html?_nkw...tering&_sop=10

1G1Y32DWXD5103335 - 2013 LS3 Corvette, confirmed by SPS to be a manual trans

This is real easy, guys.

Are the tables different in different year ECMs? In other words, is there going to be something in the 2013 ECM that would be beneficial when tuning a turbo 6.0L ? (vs an E38 from a 2007 or 2008)

I was about to order an E38 programmed for a '07 Vette (since I have an LS2, I figured the tables would be pretty close to start with) but then saw how much an LS2 throttle body costs ... and can't seem to find any used ones in Canada...

[blindsquirrel]

There are quite a few oddities in the early OSes. You can go to the repository and download all kinds of different files from the different years and check them out. They do all use VVE (they're torque based, unlike the Gen 3s & E40s which were airflow-based), but the format of some things like injector data were kinda weird in '06 & some '07s.

Go to the repository. Grab a bunch of candidate files. Look them over (does a particular OS have a 2-bar upgrade available? - not strictly necessary, but nice, VVE is kinda ick though it can be made to work). Find one that has the stuff you want, make sure it isn't a one-year-only thing that's hard to find and costs $900... I think I can save you some of that time and tell you again that the '10-up E38 service number of 12633238 with a '10-up Corvette OS is probably going to be the cheapest, and most features, and widest compatibility with other components, and the most 'universal' when it comes to finding information about how they work and what the quirks/workarounds are.

[Agtronic]

Thanks for the info, brother. Much appreciated. Going through some tunes would have been my first approach, but unfortunately I don't have a Windows machine at the moment. I have go get one.

I'll have to do some research regarding throttle bodies etc... A quick Google search shows the LS3 'Vette having the LS2-style throttle body. I was hoping to use the stock pedal in my BMW as it is hinged at the bottom (as opposed to over-hung GM pedal). There is a guy over on the bimmer forum who did some extensive testing with this pedal on an E38 LS2 Corvette OS and it's been going strong without any issues for over 6 years. It just requires a ~1mm spacer on the closed stop point so that it doesn't go below a certain voltage when closed. But from what I've read, pedals/TBs are very touchy with the E38 so I'll have to do more reading on this.

Thanks again!