Car's mileage as indicated by Autoscan?

[Rembrant]

Hi Folks,

Sorry if this is a dumb question...

The mileage, as indicated by a VCDS autoscan is simply the mileage that is saved in the instrument cluster, correct? The car's actual mileage or the mileage as saved in the instrument cluster is not written or saved elsewhere in the car's system? (Mileage is not written to or saved in the ECU?).

I assume that an Autoscan is reading the car's VIN from the ECU and the mileage is from the instrument cluster?

Friday,25,September,2015,15:58:16:24871
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 8.1 x64
VCDS Version: 15.7.1.0 (x64)
Data version: 20150904
www.Ross-Tech.com


VIN: 9BWGP21J434076580   License Plate: 
Mileage: 110490km-68655mi   Repair Order: 



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 1J (1J - VW Golf/Bora IV (1998 > 2006))
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
          76
 
VIN: 9BWGP21J434076580   Mileage: 110490km-68655miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 038-906-012-AGR.lbl
   Part No: 038 906 012 GN
   Component: 1,9l R4 EDC G000SG  4308  
   Coding: 00002
   Shop #: WSC 00000  
   VCID: 62CB85DFEE2E962E2B-4B00
   9BWGP21J434076580     VWZ7Z0C7151692

 

[Jack@European_Parts]

Incorrect that EDC15 stores the Miles in engine eeprom and airbag eeprom .......in addition to cluster with shared gateway.

 

[Rembrant]

Incorrect that EDC15 stores the Miles in engine eeprom and airbag eeprom .......in addition to cluster with shared gateway.

Thanks Jack. Ok, understood.

This leads me to my next question then: This particular car...the one I did the Autoscan on above, was a car that was for sale that I looked at on Friday.

The car looked like it had many more miles on it than what was on the odometer and what was indicated on the VCDS Autoscan.

Just for kicks, I ran a Carfax on the VIN in the Autoscan, and it showed that an insurance claim had been put through on the car in 2013 (front end damage @ $3900). The Kilometers listed at the time of the insurance claim was over 273,000.

I passed on the purchase obviously...but I'm just curious how/where the mileage was changed on the car?

 

[Andy]

You can always try the EDC Mileage Checker in the Applications screen:

http://www.ross-tech.com/vcds/tour/EDC-15-Mileage.html

There are "odometer correction" tools out there, that are used to edit the EEPROM data in clusters to roll back odometers. It's possible that in this case, the cluster was swapped for some non-nefarious reason but you did well to trust your senses and do a CarFax on it.

 

[Uwe]

The mileage, as indicated by a VCDS autoscan is simply the mileage that is saved in the instrument cluster, correct?

Affirmative.

The car's actual mileage or the mileage as saved in the instrument cluster is not written or saved elsewhere in the car's system? (Mileage is not written to or saved in the ECU?).

Some ECUs calculate mileage independently by integrating vehicle speed and time.

I'm just curious how/where the mileage was changed on the car?

There are tools out there specifically designed to get into instrument clusters via various back-doors and "adjust" the mileage displayed by the odometer.

Early on, (a decade and a half ago) there were quite a few people who asked me to add such capabilities to VCDS and I outright refused, telling them that I want no parts of enabling such fraud.

Another possibility is that at some point, the cluster was swapped out for another one, perhaps from a wrecked car with lower miles, or even a brand new one from the dealer, where it's still possible to roll the odometer forward using a legitimate tool such as VCDS.

-Uwe-

 

[Rembrant]

Ok, that's exactly what I wanted to know.
A basic VCDS Autoscan is just going to show me the mileage that's indicated on the car's odometer.

 

[Uwe]

Yep. Depending on the cluster, it could be off by +/- a single-digit number of km, this being due to the resolution of the data the cluster is willing to provide to the scan tool.

-Uwe-

 

[Rembrant]

You can always try the EDC Mileage Checker in the Applications screen:

http://www.ross-tech.com/vcds/tour/EDC-15-Mileage.html

There are "odometer correction" tools out there, that are used to edit the EEPROM data in clusters to roll back odometers. It's possible that in this case, the cluster was swapped for some non-nefarious reason but you did well to trust your senses and do a CarFax on it.

Thanks for this. I just checked it on my own car, it worked perfectly. I wish I asked how to do this before paying the money for the Carfax...lol. Doh.

I had assumed (incorrectly obviously) that the mileage in the Autoscan was actual. It only occurred to me that it was not when the car's odo mileage was the same. It made me question it.

Thanks again,
Rem

 

[Rembrant]

Yep. Depending on the cluster, it could be off by +/- a single-digit number of km, this being due to the resolution of the data the cluster is willing to provide to the scan tool.

-Uwe-

Yes indeed...
I just checked my own personal car:

ECU: 305095 Kms
Odo: 305934 Kms
Autoscan: 305930 Kms

So, if a seller simply swaps the instrument cluster, the ECU should still show me the correct/actual mileage?

Assuming that is, that the seller isn't more advanced and does not have the equipment to modify what's in the ECU?

I'll know where to look next time at least.

Thanks again gentlemen.

 

[Uwe]

ECU: 305095 Kms
Odo: 305934 Kms
Autoscan: 305930 Kms

As mentioned, the ECU keeps track independently by integrating vehicle speed and time, rather than counting individual pulses from the VSS like the cluster does, so a small difference between the mileage in the ECU and the odometer is expected. Note however that not all types of ECUs do this, and some we haven't figured out the correct back doors to read the data from.

The channel we read from the cluster gives us km * 10, so the last digit in the Auto-Scan will be zero. Not sure if that channel simply rounds down or whether it will round up with the last digit of the odometer reaches 5 or 6.

So, if a seller simply swaps the instrument cluster, the ECU should still show me the correct/actual mileage?

The correct mileage on the ECU, yes. Keep in mind ECUs sometimes fail too, and it's possible someone may have swapped in an ECU that has more miles on it than the car it's installed in.

Bottom line: Gather as much info as possible. Condition of the car, Carfax report, dealer service records, etc, etc.

-Uwe-