Can dealer detect tuning

[CHEVROLADE]

my 09 is tuned and its been to the dealer twice, the dealer can detect it but why would on star even wanna know?

lmao thats what i was thinking,ill tell u one one thing they do know when your doing donuts,dont ask how i know

[Frenchy]

Oh yeah, we know. OnStar don't though.

[6gear]

So even though and engine is returned to stock tuning the dealership can still detect it? So is the only way around this to purchased a spare pcm?

[KeJessie]

My girlfreinds father works at the local Chevy dealership and has told me that they have to put your vehical on a computer anytime warranty work is needed. I dont know all the details but apparently they can detect if any tuner has been put on it. I guess I can look at that as a good thing about my warranty ending a long time ago lol

[bam]

I like the idea of having a stock pcm to throw in. anyone know what i should pay for one? Do i have to buy from dealer?

[6gear]

I like the idea of having a stock pcm to throw in. anyone know what i should pay for one? Do i have to buy from dealer?

Same here I would be interested in doing the same thing but would the different computers show a mileage discrepancy?

[txarkitekt]

Same here I would be interested in doing the same thing but would the different computers show a mileage discrepancy?

No.

Spare PCMs are anywhere from $20-$40. I did this with mine. Its always good to have your stock, unmolested PCM to plug in...

[Z'06]

Something to consider: I recently asked my dealer service rep if the dealership could reprogram my PCM if I change my gear ratio. The answer is no - that the dealership is no longer allowed to reprogram for gear ratios. Therefore, in order to correct my odometer and not have the speed sensor throw a code, what other choice would I have but an aftermarket programming/tuning? So naturally after a gear change, I would instruct the service rep not to plug into the PCM so that they do not override the corrected/reprogrammed gear ratio. The dealership would be on the hook to reimburse the customer to make it right again.

Just some food for thought.

[GasGuzzler]

I wish techs could use spelling and grammar better on the interwebz.

No, we don't look for tunes as a rule. There is no magic computer that tells us thus. There is no policy that makes us look for tunes on everything.

Yes, we can detect tunes on SOME newer CAN-bus systems but GM's system is fairly unreliable on proving a non-stock file. Yes, GM is now putting pressure on the dealer to actually provide a snap-shot or even a digital picture of the TechII calibrations installed screen on some (means more in the future likely) major powertrain failures. Yes, a tech can waste his flatrate time searching for mods and tunes on stuff all day with the hopes of trying to make a case for the dealer to decide to deny warranty. Then again, we need work to pay the mortgage and would rather try to deny warranty in obvious cases of abuse instead of tunes.

There were about 7 other misnomers in the topic I may not have addressed properly.

[GasGuzzler]

Oh yeah, anyone on the internet, on TV, or writing in a magazine that's affraid of OnStar is pretty small minded when it comes to tunes. It makes me wanna puke (while laying flat on my back) when I hear someone talking about pulling the OnStar fuse to tweak the computer or even use a crappy hand held.