It seems a common trend in ECU modification is the swappable tune. This is when the tuner hooks up a laptop, uploads the new maps to your engine control module, then hands you a device that enables you to change back to a stock fuel map/tune at your will.

Some of these tuners claim that it is undetectable by the dealerships, however, I am hoping to receive clarification or gurantees from the tuners about this. I have witnessed many ecu tuned german cars come through the previous partner shops with this same claim, however they have all been detected.

I know on the german cars, there is a counter in the ecu and each time the ecu receives an update or tune, that counter changes and indicates one, if it is unaccounted for by way of dealer initiated update, the ecu is scanned further and voila, voided warranty. This scenario actually happened to me shortly after purchasing an "undetectable" tune. (and yes it was set to stock)

Is this the case on the GM ecu? I would presume that given the ecu and a laptop, it would be easy to see if there has been an unaccounted data entry. I do not want anyone to roll into a dealer for a major repair to find out that their warranty isnt covered as a result.

I am hoping I can hear back from some tuners who are doing this professionaly, as your knowledge is a wealth more than mine. Hopefully we can clarify this situation.

 

As for Trifecta, Vince's tune looks like a stock tune when you pull it up on the Tech 2. The counter also gets reset to 1 when the tune is put on.

Trifecta is the only one that claims to be undetectable and has been tested to be undetectable.

with HPTuners, I think most either have a separate ECU or they do a write entire with a stock tune and it looks like it has only been written once and it looks stock.

 

There is NO way for GM to tell you were tuned by scanning the ECU, as long as you do a write entire with HP Tuners or you re-flash it back to stock using Trifecta's software. If you take the car in using Trifecta's stealth tune and they scan the car with the tune deactivated it will show as stock, but GM has a service bulletin out now warning dealerships to scan in comp mode (most common way to activate Trifecta's Select-A-Tune) and they will see the tune.

There are rumors all over the internet saying that they have some way to count how many times it's been flashed and all, but I've never seen any proof of that.

 

The last part is this:

If your engine went out, then there is a strong chance they would send the ECU in to the engineers for testing. The tune would look so different that it would be obvious, even if the numbers read it as a stock tune.

 

My primary concern, and reason for posting this, is because I want to make people very aware of the warranty risks associated with this. If you are tuned and something goes wrong, and they have so much as a vague concept that its tuned, your warranty will be voided. They will not abide by moss-magnuson act, they will simply say no to any warranty work.

The trifecta tune may be the only one that claims to be stealth and undetectable for the cobalt, but this trend is across the board with the same principles in place. VW/Audi group CAN detect tunes, even if the tune itself can not be detected, the anomalies it creates can, which they view as enough evidence to invalidate a warranty claim. As far as I am aware, these anomalies are present in the snapshot created when a CEL is triggered, by ecu access log, by advanced analysis of the ecu (they send the ecu off to their engineers lab, some mystical place where magic happens and they invent new ways to screw the consumers). Typically, theres no need to send off the ecu, but in high-profile cases, it is done.

Doesn't the ECU keep a record of access attempts? If a tune is loaded, the access attempt is logged seperatley from the flash counter. I could be mistaken when it comes to the GM ecm.

 

It can be achieved with either tune, many people have proven it (gm tech's) with HP Tuners on the HP Forum.

 

In the end, it really comes down to taking a risk. If you want to play, be prepared to pay. Otherwise just go GMS1.

 

the other thing i thought about: When there is a massive failure, doesn't the ECU take a snapshot of the current sensor readouts? Can the snapshots be erased by unplugging the battery? If not it would be obvious if you had something like 23psi at 4k RPM or something like that on the snapshot.

 

yes, I agree whole heartedly, but wouldnt it be nice for all the youngsters (that dont truly understand what their getting in to) to detail out how and what their taking a risk on, how the process works and how "undetectable" these things really are in order to spare them thousands of dollars? I mean, i keep hearing this you gotta pay to play, but if your going to REALLY play, you arent going to pay for a generic flash tune, youll get a proper tune after youve built the rest of the car to play.

So, just to detail this out, "undetectable" really means that when the tune is set to stock it is not immediately evident to the technicians.

Methods of detection for these undetectable tunes consist of:
1. If CEL or stored code is present, snapshot will reveal tune
2. Advanced ecu diagnostics from engineering lab.
3. Flash counter inconsistancies.
*awaiting confirmation as to wether or not the GM ecu logs access attempts, as that will be the smoking gun in these instances.

Again, i am not trying to be a killjoy, I just want myself and other people to understand the technical aspects of these, and that they are risking their warranties. (obviously if you are still concerned about your warranty, you aren't in the big leagues, but for those that want to keep their warranty, ima try to help you)

 

bcm records the flash of the ecm or thats just the lsj's?

 

What about a second ECU ? Youd be safe then?

 

Again, plenty of people have proven it IS UNDECTABLE when flashing the correct way with HP Tuners. I have personally had my car to the dealer and checked and they verified it was untouched when it really wasn't. A couple members on HP Forums work at dealerships and have also tested this to be sure it was working, and they verified it looks untouched.

When you do a write entire it clears that flash log, that only shows when you write a calibration to the VCM. You need to drive the car shortly after for the emissions systems to be ready but if you can not drive the car, just say you tried to clear the code quickly to see if it was something dumb, this would show the samething.

 

A write entire w/ HPT, would overwrite any snapshots on the ecm.. It rewrites the entire ECM.. just like the name says..

of course, it also deletes any code you might have.. and all the drive cycle tests will be incomplete..

BYT beat me..

Thats a dirty rumor

 

I'm a turbo LS and I still bring my car in to Chevy now and then... All under warranty work. Nothing has been voided yet surprisingly lol. Also have Trifecta tune. I'm sure they will void it most of the time, I'm just saying it's possible to get warranty work done still though.

 

no, your ecu is matched to your vehicles VIN. It would be spotted.

Couldnt you just reference this date with the vehicles birthdate/subsequent updates and determine that it was an undocumented/inconsistant flash?

 

Not if I tune an extra ecu and keep my oem ecu un touched! I took my car in with stock ecu and they never say anything. I just keep my tuned ecu at home!

 

Im going to mail you a 6-pack of liquid GOLD sir. no flaw in this that I can see.

I just drove an SS out of Colorado back to DC

 

This is what I was wanting to do. Puchase an ecm send it out to have the base file written. Im GSM1 so I planned on getting a Trifecta base file then HPT over that. All on the extra PCM. That way vin matching would not matter. Any problems just swap my old ecu in and should be good to go.

If you order one thru the dealer Id be willing to say it isnt vin matched untill you install it and write it?

 

Wrong. Both ECUs would have the same VIN stored. That's the point of a second ECU. IT would look exactly the same as stock.

 

it would be documented that the specific ecm ordered is now associated with your cars vin. Perhaps the ecm "vin" isnt the right term, I should use "unique identifier". Id presume the uniqe identifier for each ecm is directly tied to the vin. If the dealer orders a new one, its accounted for through documentation.

Importkiller's post above is a pretty air-tight solution.

 

Each ECU has a serial number. That serial number is associated with the VIN.

 

Ok, how about this.

I have a GMS1 tune now. Could i get a junkyard cobalt ecm and have that trifecta flashed and then HPT that, would that be the best idea?
that way if the dealer tracks the ecm, the junkyard ecm wouldnt show up. and swap back to 'real' ecm for service?

 

Yes, this is what importkiller posted. I can't find any technical flaws in this at all. Go for it!

 

The only thing i was concerned with is getting a spare ecm from the junkyard. from any model other than a SS, cause im sure there arent any junkyards around here with a turbo SS in them lol

 

Just make sure you get the right part number (part number is on a sticker on the ECU), but the SS/TC, Solstice GXP and Saturn Sky all use the same ECU. I bought my ECU online, it was listed as being a replacement ECU for an Opel GT (also uses the same ECU).