hey guys,

im about to finalise a deal on a 996TT, and the car has moderate k's on it, but am sending it in for a PPI on monday to make sure all is above board.

I just wondered, is there any possible way that the dealer can tell if the speedo on it has been wound back?

i purchased my GT3 with no worries about this, because the car was known locally and i trust the mileage, but the TT is on the other side of the country and i just want to be sure that if it has been tampered with that the Porsche Dealer will be able to tell? other than the usual tell tale signs.

Cheers in advance

Looney

 

odometer is stored in the ecu. if that's changed, plugging in a OBD2 scanner will tell you the VIN doesn't match the car.

 

that is not correct. in the 996 the mileage is only stored in 1 place, an eeprom chip in the cluster. the mileage is not stored in the ECU. however the ECU stores hours of operation and if you read those out and compare them with a mileage - the ratio should be resonable. however there is no sure tell formula here.

Run a vin check to make sure mileage increases consistently

 

Get the number of hours on the engine from the PPI. If the miles/km's per hour is very high, it is suspect.

 

OK, so there is no sure way to be certain, but the common sense things apply. i guess the dealer will be able to get a good idea for me though (i hope).

thanks for the input guys

 

Right, the ECU will list hours of operation.

Multiple by 30-35miles per hour (or 50-55kph) and compare that number to the speedo.

If the ECU says 1000 hours, but the speedo shows 20,000 km...something is fishy, the cars average speed was 20 kph and that is way too low.

Anything can be hacked and changed. You need to look at everything and make the call based on all factors.

 

I think they can estimate the true mileage by measuring the working hours with a 10% deviation

 

i dont think there is a sure way to tell the exact % deviation. everyone uses these for different purposes. some for daily driving, some for recreation and weekends only. hours of operation can depend on that too. if a person spends an hour a day sitting in traffic at 10mph vs a person who only drives at night with no traffic just for fun. as i said in my previous post you can use this info as a guide, but the math won't be exact.

 

Are you sure the mileage is only stored in one location.

Just before I bought my MY2005 tt I had a Porsche tech connect it to his PIWIS thingy and it showed the usual stuff such as operating hours and over revs etc but it also showed the distance covered in kilometers.

My speedo is in mph so we changed it to KMH and compared it to what the tester was showing. It was about 250 km different which he said was usual.

He said it was easy to change the distance shown by the cluster but very difficult to change the distance in the DME ??

I've since bought a Durametric and it shows everything the PIWIS did but not the distance?

We also worked out the average speed and it was about 30 mph.

And