how much is an ecu?

[flyfishing]

How much is a spare ECU? Can you just buy one and plug it in?

I ask cause I really wanna ecu tune but don't want to void warranty. If I could plug a different one in when I go to dealer, then no biggie :)

[DoughBoyFreshLV]

http://www.ebay.com/itm/191704251535?redirect=mobile

[VVG]

I did this with my B5 S4. I had 3 ECUs. Stock, APR and a custom tuned one. Switched them out at will. I don't know if you can do that on today's cars, however. If you can, I would be all over it. Anyone?

[jrsAudiA6]

When I looked up the ECM P/N for a 2012 A6 3.0T I found it do be 4G0990990A were the one shown on EBay is 4G0907551D which is for a 2013 A6 3.0T according Audi Online Parts. Their cost for new ECM is $1232.40. I do not think it is as simple as swapping these out between a factory tune and a non factory tune. Hopefully someone with knowledge can pipe in on this subject.

[yas]

I believe it's complicated, and involves reprogramming the key(s).

[agent47]

@sciblades wanna chime in?

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[bhvrdr]

Ever since around 2002 the ECUs have had more advanced immobilizer functions that includes the programming of an SKC at the dealership. In short, the ECU is programmed to your VIN. Only one at a time can be programmed to your VIN. A dealership can make an ECU swap and then mate/program the new ECU to your car but that would negate the whole purpose of having a spare stock ECU.

Mike

[flyfishing]

darn :(

[sciblades]

How much is a spare ECU? Can you just buy one and plug it in?

I ask cause I really wanna ecu tune but don't want to void warranty. If I could plug a different one in when I go to dealer, then no biggie :)

Long story short you need a tuner willing to help you after a dealership deactivated one...

@sciblades wanna chime in?

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Moral of the story if you want to spend 2500 and have a tuner on your side you are golden...

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[hubris]

I spent a lot of time researching this, finding a tuner, sourcing parts and software, and ultimately decided to not go through with it. I ended up not pursuing this route for two reasons.

It is possible, and as sciblades mentioned it will be expensive. You will need to ship a tuner your ECU and the alternate ECU, unless you can find one locally. However it takes a particular skillset to be able to perform this task. He has to physically open and bench read/flash both ECUs. The original ECU will be 'cloned', it is the only way to possibly work with this generation of ECUs.

1. The ECU does not work independently. It communicates with many other modules in the vehicle, many of which could be storing data. Thus my theory is as follows. If any data is stored in another module or anywhere in the vehicle about mileage (keep in mind there would be an inconsistency as soon as you swapped the ECUs since one was logging miles while the other was not), boost or anything else, you're SOL. Audi Germany will analyze logs if you need a costly repair, and they could find this data. Then consider that there's a pretty good chance it trips some kind of wire or flag when you swap the ECU. Yes, it was cloned... but that was at a specific day and time. The miles are different, the SW version could be different if you've gotten updates since then, etc.. MANY potentials.

2. Audi Germany often sends out a physical engineer to inspect vehicles if these costly repairs are needed (turbo, engine, trans, etc.). You can be certain they will at least visually inspect your ECU. First off, that ECU is locked in by security bolts. You better plan on replacing it with OEM bolts ($$$) every time you swap your ECMs, or that will be the first visual clue that somethign is off. Then, if they open the cover, it will be evident that your ECU was physically tampered with. It will have tool marks, etc...

Now both of these reasons are obviously based on 'best guess' scenarios and strictly hypothetical. However all of the added cost and hassle of maintaining two ECUs is not worth it for me. It's a gamble. If you want to spend $1200 for an ECU plus $2500 or more for tuning and think it MIGHT help you, but more than likely it won't, then that's your choice.