Speedo works, Odometer doesn't..

[PS78]

...some owner's dream?!...not now I'm about to go through the 3rd UK MOT roadworthiness test with not a mile more on the Odo than at the last 2 MOTs!.... This 2000 GTS, sold to me by a very well know LA Viper '''''specialist''''', with the description stored-for-years, very-low-mileage, has an odo reading of 1089 (yes, i shouldn't have bought it.....).

The speedo unit is out at a local well know ex-viper racing service garage, who aren't able to test it with their more modern kit (and they race porsches now)!... Ditto at local Dodge dealer, who can only test back to Gen3.

So...has anyone seen this issue before ?
Is it definite faulty unit - get a new unit?
Can a new unit be got and how does one set the odo??

Please, thank you!

[PS78]

or maybe a sensor issue?

[luc]

or maybe a sensor issue?

Do you realize that the thread was 2,5 years old???

[PS78]

yes!.. and the mystery still goes on Luc!..not so easy to solve outside the USA. Do you know about Odometer issues? If the Speedo works, but the Odo doesn't, is it the gauge that's scr3w3d?

[Boosted Motorsports]

Rare issue but I would try a new gauge. If it was a newer car with a digital odometer it would be a different story but with it being a mechanical odometer it is most likely going to be an issue inside the unit. I'm sure you can pick one up pretty cheap to try and would be the easiest solution.

[PS78]

Many thanks Boosted. New Gauge has been recommended by one garage but as a default diagnosis "after we've tried everything else, so it must be the gauge(??!)"

[AZTVR]

yes!.. and the mystery still goes on Luc!..not so easy to solve outside the USA. Do you know about Odometer issues? If the Speedo works, but the Odo doesn't, is it the gauge that's scr3w3d?

The Speedometer gauge has no mechanical input. There is one wire coming from the PCM that provides a pulsed voltage which is derived from a sensor in the transmission, indicating each rotation of probably the output shaft. (The other wires provide battery voltage, lamp illumination voltage and ground.)

Therefore, if the speed indication is correct and the odometer reading does not change, the logical conclusion is that the pulsed voltage is correct and is making it through the connector to the portion of the gauge that makes the speed indicating pointer deflect. I would conclude that either the odometer motor is bad, or the drive connection is slipping, or most likely there is a bad solder joint or bad connection that could be fixed by a DIYer after cutting open the speedometer. (which is illegal here in the USA, I think.)

I do not know for a Gen 2; but, the PCM may store a mileage calculation also.

[Fatboy 18]

Hit it with a BIG STICK

[Boosted Motorsports]

I'll trade you for mine with 71,000 miles on it for yours that works like a collector's dream

[ducatithunder]

I'll trade you for mine with 71,000 miles on it for yours that works like a collector's dream

LOL. I was wondering how there wer so many sub 3000 mile gen 2's coming on the market.

[Fatboy 18]

How about one in the UK with 86.000 on it

[Viper Red]

My first Gen1 I bought back in 2006 had this issue. odo didn't work and was stuck at 23k.

[PS78]

AZTVR- thanks for your insights...one garage has already had the gauge apart and got as far as 'the chip'. Found nothing wrong in the gauge and assumed it was this chip....but as always here ,with Vipers so rare, the diagnosis didn't give me 100% confidence....so since it's been dismantled already, I'll give it a go and order another, if I can get one, reading 20,000miles or less. The PCM has been read before here, at a Dodge Jeep Chrysler dealer, before it closed, soon after I got the Viper, with a reading of c16000miles.....bit different to the stuck 1065 I nieavly bought it from DC Performance. But I couldn't be sure it is even the original PCM fitted!.... The Car has had a fair few alterations from stock to run in the US Road Racing series.
Marky Fatboy!...if all else fails....you can have a go at electrical/gauge tinkerings!!!

- - - Updated - - -

My first Gen1 I bought back in 2006 had this issue. odo didn't work and was stuck at 23k.

Did you solve the problem, VR?

[AZTVR]

..so since it's been dismantled already, I'll give it a go and order another, if I can get one, reading 20,000miles or less.

There are two on eBay, one that appears to be an export model in KPH and one USA standard in MPH.

[Fatboy 18]

There are two on eBay, one that appears to be an export model in KPH and one USA standard in MPH.

Got a link? Im not finding them?

[AZTVR]

Got a link? Im not finding them?

https://www.ebay.com/itm/2001-Dodge-.../332440044705?

https://www.ebay.com/itm/DODGE-VIPER...2/172894172990

[Fatboy 18]

Thank you

[PS78]

Now to find a PCM mileage reader.....!