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Question folks,

Looking at a 997.2 GT3

Very clean car, 1 owner, now at dealer. FS with a CPO.

Odomter reads roughly 8300 miles. A carfax through a flag of inconsistant odo reading. There was some service on the CARFAX report in 2009 and indicates a mileage reading of roughly 9200.

How common is a clerical error?

How common or possible is it to role back an odometer?


Tim Scanlan



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Someone would have to replace a lot of internal very expensive components such as instrument cluster, perhaps additionally ECU and alarm modules, and the donor car would need very low miles, making it even less likely.

Perhaps the carfax service or other report was a typo.

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Have the dealer's technician use a PIWIS to read the operating hours and multiply that number by about 30-32 mph. The result should be a fairly good approximation of the mileage. As "logray" says, it would take replacing at least the instrument cluster with a new one (or having had the original one reset by an instrument shop) to lower the indicated mileage. And, that would not address the operating time issue. The DME would have to be replaced with either a new one or one from a low mileage used car. It is pretty difficult and expensive to roll back mileage with out a smoking gun. And while you're at it, have the dealer's technician use the PIWIS to read the number of "ingitions" the engine has experienced. Type 1 ignitions indicate the number of times the rev limiter was needed to kick in to keep the engine from exceding the red line. Type 2 through 5 (?) indicate actual overspeeding of the engine - generaly caused by a missed down shift, i.e., shifting from 5th to 2nd missing the intended 4th gear. Every ignition reading is accompanied by the last operating time at which it occured.

Was the instrument cluster ever replaced? There is a spot in the front of the Maintenance Booklet that would show the fact and the mileage/date at the time of the replacement. Also, are the maintenance records available? If so, the replacement should have been recorded. Have the dealer check the Porsche system wide computer data base to see if any warrantee work has been done.

There have been problems reported with the accuracy of CARFAX reports in the past. I would hold the dealer's feet to the fire to get the question resolved before any cash changes hands.


Edited by whall
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Doesn't the DME store the distance traveled separately from the instrument cluster as well? OF course, as pointed out earlier that could also be replaced, and although there are some keen individuals who can tamper with the DME maps, I'm not sure if odometer or operating hours could be changed as well. All of this would be at considerable cost to the person doing the changes, mind you.... eating into their profit ... and unless the car had been driven many 10's of thousands of miles it probably wouldn't make much sense, not to mention illegal.

Maybe the maintenance records will have an odometer reading on them, further proof of a clerical error?

Edited by logray
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Doesn't the DME store the distance traveled separately from the instrument cluster as well?

Yes it does, and you are correct, it can be viewed in the DME Vehicle Data using a PIWIS. You will find a small difference between the reading in the DME, and what is shown in the instrument cluster. This is because the instrument clusters over-read speed and mileage by up to 10%

Another good check is to look at the Airbag module data, which has a separate hours counter. Compare this to the DME hours counter, and it should be similar. Again, there will be a small difference, but if it is a large one it needs investigation. People may think about replacing or hacking the DME and Instrument cluster modules, but don't consider the airbag module.

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  • 4 years later...
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I'm not sure what you are trying to get at, and most of the links you have posted lead back to this thread.  If you are asking can the odometer be messed with, the answer is yes, but not very easily.  It would require specific knowledge and shifting a lot of component's that all track the car's run time.  If you are concerned about buying a car without seeing or evaluating it, that is a total crap shoot.  If someone has taken the time (and expense) to try and hide the car's actual mileage, it might not be caught in a full PPI.


Probably the best advice we can offer is to tell you that if you get a feeling something is wrong, don't move forward.

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It all looks a bit suspect to me. 

18000/580=31kph average (19mph).  For a GT3?

The airbag module reads 830 hours.  This starts counting when the ignition is switched on, whereas I think the Operating Hours counter in the DME (580 hours) records the engine running time.  You would expect a discrepancy, but 250 hours?

And the ignitions in rev range 1 only 79, 22 hours ago?  It is a GT3 after all, and you would have expected some slightly more spirited driving than that during its life, assuming it is manual transmission.  Even my Cayman 2.9 PDK had some in rev range 2.

There may be a plausible explanation, but unless the seller can provide one I would be very suspicious.

Edited by Richard Hamilton
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Possible they switched from miles to kilometers? Or that it was just left in someone's garage and taken around the block every now and then to keep it in top shape? Call me racist or whatever but doubt a GT3 is being used often on the roads of Mexico.

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