Originally Posted by gthal
Hi Mike. Your input is appreciated, especially considering you know more than 99% of us here on this issue. I do have a question. You seem very confident that the dealer would not find evidence of a tune. Why is it that both Evolve and ESS have suggested that if there was a major issue with the engine and BMW investigated that they would be able to detect a tune. Maybe the distinction is that the dealer could not find it unless they had BMW involved? Anyway, if you could clarify it would be appreciated as other tuners don't seem to be as confident (or at least won't put it in writing here) that you would never have a warranty issue.
To answer your questions:
If there is a major issue, it's always good to go back to stock. However, it's very unlikely that they would ever find an ECU tune as the culprit for whatever problem is at hand.
What the OP experienced - a sensor error, is by no means a major issue. It happens all the time on bone stock cars.
If BMW was involved and they did suspect foul play (which there is no reason to in the first place), there is potential that they could find out about it. It's not easy though and would require time and money investment on their part. It's sort of like chasing a goose. Unless there is something directly pointing to a flash, there is no reason to suspect it. A check engine light coming on is obviously normal operation if something called for it to illuminate.
My CEL came on a few weeks ago and it turns out something hit my post cat 02 sensor under the car. Even though my car is programmed to ignore readings from that sensor, the sensor still has to be in good shape and intact or it will still throw a CEL.
CEL's are supposed to be set for a reason, and the tunes retain all of this programming. Now, a different story all together, is a strange code being thrown, or an internal DME fault code which would indicate foul play. There are checks that the ECU goes through and if those checks are failed it will almost be a dead giveaway. Anything else is well within operating spec and you would want the light to come on if something is awry. Usually the dealer will just flash the ECU when they have no clue how to fix it, which wipes the tune out anyway.
The only car I've heard of having it's warranty voided was a car in Singapore. The guy had a tune that he would not disclose and dropped a valve on the track. They refused to pay for the engine in this case.
However, in the US, I honestly can't see something like this happening unless there was a clear indication that the tune caused issues. And if it worked for the first week, it will probably work for the life of the car. There is always the chance that incorrect programming could cause errors in different climates or conditions, but if you leave it to a professional, that should never happen.
Going back to stock is an added layer of protection, but it's not really back to stock. There are flash counters that will be incremented, potentially a UIF write, and the program side of the ECU is locked from OBDII access, so to get around stuff like that you would need to bench program (BDM) the ECU. And that will leave physical signs of tampering which is even worse..
Also, the piece of mind that people get with a Dinan tune is a joke.. It's the same thing as with any other aftermarket tuner. It's ridiculous to say that a tune caused an issue with a car unless the programming is off. Drastic changes will cause this, and tuners that don't know what they are doing and hunt around and go "Oh, maybe this is it, let me try to modify this", instead of having the proper files which indicate what these locations actually do, and how they affect other ECU functions.
Downgrading to an earlier software version is more of a giveaway, however, this can be a difficult one too for them to notice depending on whether or not the UIF is written to the car. The UIF is a 'directory' of software revisions the car is programmed with. I can write files all day long without writing the UIF and it will appear that the original software version was still in there even though the code has been modified. It comes down to how much BMW wants to invest in denying a claim. If there is no reason to suspect a tune (as there shouldn't be), warranty coverage shouldn't be an issue.
OP: If you'd like to be re-tuned on our latest software version which contains some new power adders, let me know. The cost will simply be the re-flash fee, and you will get the latest and greatest programming. Totally up to you. I can check the software versions and make sure everything is up to date (ista 42.2). If something is not up to date, I can update it to the latest BMW version. The good thing about it is that I can do it selectively, which the dealer can not do. It's either all or nothing on their systems. There is a programming part and a coding part. Even if the dealership programs one module, they have to code the rest of the car. So if they programmed your ECU, the CAS gets recoded anyway which is why you lost your door locking functions. See the coding list in my signature.
Hope this helps..