Corvette-Dan

Hello. In an effort to ensure that my tune is factory stock before I dive into a custom tune I found somebody with a GM Tech 2. He hooked it up at his house and with a PC informed me that he would be unable to restore it to a stock tune. I would need to take it to a dealer so they could assign a service request, call tech support and get pass code to do this. I would hate to pay a dealer only to find out that it is already stock. I do have a print out of what was found. The first number on the list is preceded by an asterisk (*) which I was told could be an indication of an aftermarket tune. I am hoping somebody here can recognize the information and be able to tell me if the current tune is GM factory or not.

What I have is:

Powertrain/Vehicle Control Module
VIN: XXXXXXXXX.........
Vehicle Data
Controller Id Current # Selected # Description
PCM/VCM 1 *9378021 12584929 New software to address customer complaints of erratic fuel gauge, DTC P1431 and spark knock. Replaces all previous software.
2 Unknown 9358690 New calibration to address customer complaints of erratic fuel gauge, DTC P1431 and spark knock. Replaces all previous calibrations.
3 Unknown 9359054 (followed by the same message as in 2)
4 Unknown 16264208 Running change for software level upgrade
5 Unknown 16253322 Transmission Diagnostic
6 Unknown 16264708 New calibration to address customer complaints of erratic fuel gauge, DTC P1431 and spark knock. Replaces all previous calibrations.
7 Unknown 9373669 System calibrations
8 Unknown 16253371 Speedometer calibration
Attribute Value

Although this person is not the Corvette Tech he is fully qualified by GM standards to service GM vehicles. I know how crazy GM can be so I not going to officially say what this person currently does for a living. I just want to remove the possible assumption that the help I received was from somebody unqualified. I just want to know if I have a stock tune and if you would know why he could not reflash it.

Thanks!

K-Spaz

I'm new to this, but would it not be easier to just use HP Tuners compare function and look at a similar tune with your build # from the repository, and see if the stock tunes there match yours?

As to reprogramming, as I understand it, you need a subscription to TIS2000 to do programming. Can be 3 days, week, month, year, whatever.

Corvette-Dan

Yes if I had access to HP Tuners I would. Anybody in the Chicago are with one willing to help out?

tblu92

A TECH II cannot re flash an ECM It is a diagnostic tool used to diagnose issues with all your car's computers ECM/BCM / ABS ----In order to do a relash back to stock you need other software The dealer does have alternative software programs to flash your ECM back to stock But it is NOT the TECH II Many repair shops have the TECH II it is common software for any shop to do diagnostics ONLY
You can have the dealer reflash your ECM back to stock for like $150 OR you can have a tuner do the same thing--someone with HP or EFILIVE However the benefit with a tuner having HP or EFILVE is that they can "compare" your existing " tune to a totally stock tune from a car of the similar year and same operating system----The dealer cannot compare your existing yune from a stock tune-----A tuner can compare your tune and if he deems it is indeed stock then there would be no need for the cost of a full re flash

Corvette-Dan

Thanks for the explanation. So there is no way of telling that first number on my list is a stock tune?

tblu92

No on all the older C5's C6's there is no way of checking if the car has been tuned without comparing the whole tune file to a totally stock tune
On 2014 and newer Corvettes some claim the there is a tell tale way to see if it's been tuned----It is rather complicated and is done b seeing if the "checksums" match the stock tuned checksums-----But again this can only be done with HP--EFILIVE or the dealers "back to stock" tuning software NOT using a TECH II

K-Spaz

This is not true at all. I just programmed my new PCM to stock using the AcDelcoTDS site and a Tech2. The Tech2 won't do newer cars, up past like 2008 or so, but for the C5 it's a great tool. It is also a diagnostic tool as well, but for service programming, the only thing it lacks is the ability to do that stuff without paying GM the $55 subscription fee. Pay the $55 and you're on your way.

If you want to know if the tune in your car is stock, all you need to do is get the tune from your car and have someone with HPTuners or EFI open it with the compare function and see what's different. There might be super minuscule things, but for the most part it should show no differences.

K-Spaz

It doesn't matter. All you need is to get the car running right. It doesn't matter where it's at right now.

tblu92

What to the heck you mean ? I said exactly the same things as you concerining what a tech2 can or cannot do so I am confused as ro why you say I am wrong when I said the same thing as you did

K-Spaz

Ok, well yes the Tech2 CAN reprogram the PCM. Yes, AcDelco also has other programs you need to interface to in order to do it, but the Tech2 absolutely WILL reprogram one. I just replace my own a week ago and used a Tech2 to do it, and NEEDED the Tech2 to do it.

Corvette-Dan

OK I found a great guy who compared my tune to stock via HP Tuners. This is what he said. Although there were some minor differences all the usual parameters that get modified were close to if not the exact same. Even fan temps, torque management and other common mods were exactly the same. I do know that the car was serviced a a stealership for many years and they did install updates to the car. We also speculate that the tune he compared to was a base car with a 2.73 gear and mine has the 3.15. He showed me where the two would differ and they did slightly. Sorry I do not remember exactly what those areas were as it was hard to read his laptop whlie he was comparing without getting in his face per se.