Vehicle Odometer Increase Reading

Thread Starter

Kevinlinnane

Joined Feb 8, 2020
3
Hi, appreciate any insight into this query.
Long story which I’ll tell again but I wish to increase the odometer reading on my Skoda Kodiaq 4X4 car (2019), by about 10,000miles

I notice if I jack up one wheel, (the front passenger side) and turn this wheel by hand the odometer increases. An ABS sensor error appeared after a while of turning this wheel in isolation.

I could arrange to get a motor to drive this wheel around and that would provide the solution but would be slow and cumbersome.

I wonder where is the odometer taking its signal from? Is it possibly from the ABS sensor at each? wheel? Or more likely at the gearbox and turning this wheel was advancing it?

Was hoping there might be a way to interrupt the signal from whatever sensor is involved and perhaps introduce a different waveform to increase the odometer reading?

Much appreciate any guidance.
Tom
 

jpanhalt

Joined Jan 18, 2008
9,043
Modifying the odometer is generally illegal, whether it is up or down. I can think of only two reasons to do that. One is illegal per se; and the other (i.e., you replaced the odometer with a new one) is better left as is.
 

Externet

Joined Nov 29, 2005
1,469
You need the service manual schematic. Likely the signal comes from sensors at wheels hubs. Then, an oscilloscope and a wave generator, and care to not damage anything while tampering. Later, an error code reader-eraser as whatever you do will not be pleasant for the on-board computer.
 

Thread Starter

Kevinlinnane

Joined Feb 8, 2020
3
You need the service manual schematic. Likely the signal comes from sensors at wheels hubs. Then, an oscilloscope and a wave generator, and care to not damage anything while tampering. Later, an error code reader-eraser as whatever you do will not be pleasant for the on-board computer.
many thanks, that was along the lines of what I was thinking.
Just wondering is the wheel speed sensor within the hub the likely sender for this info?
Or is moving the individual wheel by hand being being picked up by a sensor at the gearbox?

kind regards
Tom
 

bwilliams60

Joined Nov 18, 2012
1,282
Odometer readings can be picked up by wheel sensors or a vehicle speed sensor at the transmission or differential. It is then relayed to an ABS module and then to engine module possibly and instrument cluster module. Turning one wheel and setting a code is normal because the ABS module figures that to be an abnormal event like a spinout. It would normally try to derate and send power to another wheel. Since it cant, it sets a code. If you have legitimate reason to change mileage, people who do instrument cluster repair can rewrite your EEPROM and set it correctly. Otherwise it should be left alone.
 

Externet

Joined Nov 29, 2005
1,469
Original poster may have a reason. But doubt reversing odometer would be possible by just turning wheels. The waveform would make the odometer advance even in reverse. Not a mechanical device, and even my old '61 car has a mechanical odometer self-destruction feature if turned backwards.
 

DickCappels

Joined Aug 21, 2008
6,300
Original poster may have a reason. But doubt reversing odometer would be possible by just turning wheels. The waveform would make the odometer advance even in reverse. Not a mechanical device, and even my old '61 car has a mechanical odometer self-destruction feature if turned backwards.
That's assuming that the wheel(s) was sending quadrature pulses.

Discussing this topic may not be a good idea. The information can be used for nefferrious or illegal purposes. For example I've caught two taxies in Bangkok that show meter readings almost exactly double that of a "normal" trip. Generally odometer readings are taken as being absolutely true, and as @japnhalt points out, modifying an odometer reading is illegal in places with good reasons.
 

bwilliams60

Joined Nov 18, 2012
1,282
The only reason that an odometer should be modified is if you are replacing a cluster and want to match new with old. The recommended procedure is to put the new one in at zero and start fresh, noting the old mileage on a sticker. I like programming the old mileage in for better accuracy. It can be reversed but we would hope people would be honest about it. As far as the conversation, this is not new so people should talk about it and know that it is against the law in most countries to turn back or adjust an odometer.
 

Thread Starter

Kevinlinnane

Joined Feb 8, 2020
3
Thanks for the comments guys. I confirmed that the signal increasing the odometer was coming from the ABS sensor mounted in the wheel hub. I connected a scope to this sensor and established what the waveform looked like as the wheel rotated, including a test on the road. I then connected a basic consumer electronics grade signal generator in place of the sensor and and mirrored what I had seen earlier with the scope - extrapolated to 250mph. Seems to do the job.

Kind Regards,
Tom
 

BillB3857

Joined Feb 28, 2009
2,532
Many old odometers had a screw type mechanism that, after many revolutions in the reverse direction, disconnected the decade wheels, hence they stopped counting backwards. Resuming forward motion, after a short time, the decade wheels would engage and count forward again. This was an attempt at preventing odometer fraud. Of course, it didn't stop it but did make it more difficult since disassembly of the odometer unit was then required. Only old people remember such things.
 

Tonyr1084

Joined Sep 24, 2015
4,362
Modifying the odometer is generally illegal, whether it is up or down. I can think of only two reasons to do that. One is illegal per se; and the other (i.e., you replaced the odometer with a new one) is better left as is.
Here in the United States (Utah particularly) if for any reason you need to replace your odometer you can. However, by law, you must post the old mileage - OR you can take the vehicle with the replacement odometer to a certified shop where they can reprogram the replacement odometer to read exactly what the old odometer had on it. This should be done as soon as the new odometer is installed. Within days, within a few miles. Otherwise to do anything else is to defraud the next purchaser of that vehicle, leading them to believe it has fewer miles on it than what is actual mileage. A vehicle with an unknown mileage is worth far less than one that is known, even if the mileage is high.
Original poster may have a reason. But doubt reversing odometer would be possible by just turning wheels. The waveform would make the odometer advance even in reverse. Not a mechanical device, and even my old '61 car has a mechanical odometer self-destruction feature if turned backwards.
Advancing an odometer reading should not be so hard to do. The TS (Thread Starter) stated he wanted to advance the odometer by 10K miles. As for "reversing" an odometer - that is not possible. They are programmed to sense the amount of tire rotation by a square wave. Any and all square waves are read as forward miles. If you drove from west coast to east coast, some 3K miles BACKWARDS - your odometer will still register that you've gone 3K miles.

A few years back I bought a used truck. It had the wrong tires on it. Who knows how long they were, but the result was that if I drove a physical 100 miles the odometer would register 130 miles driven. I purchased a warranty for the vehicle, but at 30% faster burning up of the miles meant losing 30% of the warranty. First thing I had to do was get the right tires on the vehicle. That brought me down to a 9% error. Industry standard is +2%, -0%. The second thing I had to do - since this was rear wheel drive was to change the driven gear that turned the sensor magnet. I managed to get the error percentage down to < 2%. At 25 actual MPH the speedometer registered 26 MPH and at 75 actual MPH the speedometer registered 74 MPH. To achieve that I had to move the speedometer needle down to minus 2 MHP. Since little to no time was spent driving below 25 MPH I could live with the slight mis-registration of the needle. The end result for driving 100 miles was that the odometer would advance just about 101 miles. However, I never did anything to the vehicle's actual measured mileage. While researching solutions for this I learned about Utah law regarding changing odometers. So I have some real world experience in this matter.
 

bwilliams60

Joined Nov 18, 2012
1,282
As for "reversing" an odometer - that is not possible. They are programmed to sense the amount of tire rotation by a square wave. Any and all square waves are read as forward miles.
I don't mean any disrespect @Tonyr1084, but this statement couldn't be farther from the truth. In fact it is a big problem for people buying cars and trucks these days. Electronically stored mileage can be changed forward or backward very easily in a lot of cases and nobody would know the difference unless you really know your vehicles.
 

AlbertHall

Joined Jun 4, 2014
9,622
The only one I took apart (years and years ago) had a ratchet which advanced the mileage so it increased the number which ever way it was driven.
 

Tonyr1084

Joined Sep 24, 2015
4,362
@bwilliams60 Yes, I know it's possible. In fact I know how to do it. The point I was making is that turning the wheel backwards does not make the mileage go backwards. That's all I meant. Driving backwards from LA to New York doesn't make the odometer go backwards. In fact, even mechanical odometers are (or were) designed so that if you spun them backwards they would not count miles. When I was a kid I used to steal my brothers car and disconnect the speedometer cable. I never knew how fast I was driving but the mileage was not changing either.

Possible to change an odometer - absolutely. A legal way? Yes, to have a licensed and certified shop do the job. Backward, forward, it's all possible to change an odometer.
 
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