With the recent ECU flash discussions, I began wondering if the DME information can be overwritten, reset, or otherwise tampered with? Many use the DME scan as part of the buying process but if the information can be changed or the triggers modified, then isn't a clean DME scan meaningless?

If the DME information and/or ranges cannot be easily modified, then how do the tuners who increase the rev limiter prevent continuously triggering/recording overrevs?

 

In my opinion, DME information is nearly meaningless to begin with. I mean, if a proper PPI is done, a leak down test comes back clean, the car is priced fairly, are you going to walk a way from a deal if the over rev counter is slightly higher then you would like it?

To answer your question, tuners can reset, change or change limits in which DME info is calculated, but so can Porsche of America, "shady" shops that own grey market tools, and many with the knowledge to write diagnostic software. DME info isnt black and white and should be used as one of the last deciding factors on weather or not to buy a car.

 

Thanks for a great answer.

 

I just got done buying a Pcar and one of the dealers I came very close to buying a car with indicated that although the DME scan showed a pretty high number of overrevs, basically if I bought this particular car he could ship the ECU away and have it reset by the time I picked it up. This was mentioned in a sort of wink-wink-nudge-nudge kind of way over cells phones, but he was very serious about it.
I didn't end up buying my car from him, but I agree with the OP in that it really made me think in some instances the DME scan might be worthless. I'd probably be leary now if the DME scan was absolutely clean on a vehicle that is meant to be occassionally driven in a "spirited" manner.

 

I think this is an excellent perspective on the matter. But to respond to Scott's question, it is my understanding that overrevs are located on a separate chip. A person would have to physically mod the chip to eliminate them which can be done. They are working on a fix for the overrevs through the cables which can be done with 996t’s… But not right now with 997ts. If you have overrevs right now, your tuner should be able to mod your ecu so it won't count overrevs from here on out but it won't remove any that are already there unless you replace the chip.

 

You are correct, the over rev's are located in a separate chip. But, in this chip is also the DME id that is needed to log into the ecu to be able to flash the entire DME memory. Basically, this chip need to be read to be able to "tune" an the DME.

What does this mean? Any tuner or tool or program that can "flash" the DME can also alter data in this separate chip and DME info.

 

Thanks for the clarification.

 

Some points that seem unclear to me -- .

This questionable DME was posted in the 997 forum-- no over revs show up and look at the operating hours.
https://www.6speedonline.com/forums/997/190873-wacky-dme-how-does-happen.html

My feeling is try and erase whatever doubts the best one can when shopping for a used car .

I also feel that clean DME before one buys a car is a factual disclosure document and beneficial for the buyer to have it.
If its authentic then he has the facts .
If it's not then at least he has some written proof to verify that too.

 

in order to define whether a car has a "clear" DME reading (regarding miles/hours) you have to check all ECUs that have the ability to log hours...not only DME...
As far as overrevs, i would prefer a car with no overrevs...However,anything below range 4 is ok...But not over it...

 

That's somewhat my point .

The technician scanning the DME would probably be inspecting the entire car .

If so ---Inconsistencies where the wear and tear doesn't match the squeaky clean DME ought flag the car on the spot.

No?

 

I have a question, does Softronic or other tunes turn off certain CEL parameters permanently so they will not trigger?

 

Yes, they can do this for race cats, etc...and most rasie the rev limiters but not the theshold for the over-rev counter to you can click counts w/o hitting the new limit.

 

Don't forget you could also buy a new DME and it would show clean. Operating hours would be low (if total hours is even displayed) but if all you're looking for is over-revs...well there wouldn't be any.