'94 Odometer loses miles ....

[JCHarper]

Just noticed that on occasion the odometer on my '94 loses miles. Will be reading 102093 then when I start it the next day will read 102084. What's up? Does anyone have an idea? No error displays anywhere, odo or otherwise. Should I get the computer reflashed?

 

[boomdriver]

Thats a good one...

If your's is all digital with no mechanical odometer then I'd say it needs to go to the shop for rebuild/repair. Older odos like mine that were mechanical had a drive motor and I can see that running backwards, but the digital does'nt have that, so it must be in the circuit board.
See if the odo racks UP miles as the 1/10th go by as it should...might be a clue if its not adding up miles as it should. Never heard of one doing a self correction...by GPS at night?

 

[JCHarper]

Thats a good one...

If your's is all digital with no mechanical odometer then I'd say it needs to go to the shop for rebuild/repair. Older odos like mine that were mechanical had a drive motor and I can see that running backwards, but the digital does'nt have that, so it must be in the circuit board.
See if the odo racks UP miles as the 1/10th go by as it should...might be a clue if its not adding up miles as it should. Never heard of one doing a self correction...by GPS at night?

Thanx for the reply.
Yeah it's digital. Does rack up miles. Just loses miles after being off for awhile. There also seems to be a current draw when off as well, so I am having it checked out. Could even be the BCM/CCM unit, since from what I've read weird things can happen when this is not functioning properly. Or it could be just a simple bad connector or the like somewhere in the system. Electrical can be a challenge to troubleshoot. My son is ASE certified tech and we will be doing some troubleshooting to see what the heck is going on. If anyone else has been having similar issues, please chime in, would a give a place to start for troubleshooting. Whatever we find I will post so as to help anyone with a similar issue.

 

[boomdriver]

Thanx for the reply.
Yeah it's digital. Does rack up miles. Just loses miles after being off for awhile. There also seems to be a current draw when off as well, so I am having it checked out. Could even be the BCM/CCM unit, since from what I've read weird things can happen when this is not functioning properly. Or it could be just a simple bad connector or the like somewhere in the system. Electrical can be a challenge to troubleshoot. My son is ASE certified tech and we will be doing some troubleshooting to see what the heck is going on. If anyone else has been having similar issues, please chime in, would a give a place to start for troubleshooting. Whatever we find I will post so as to help anyone with a similar issue.

I'm not familiar with that yr model dash, but I DO know that the odo will have a memory chip on the circuit-board thats supported by a power chip so that it does not loose memory if/when the battery is d/c. If the mem chip is damaged somehow, or shorted it could actually discharge. Dumping its memory when turned off is interesting. To me, that indicates a short of some sort. Where is the fun part.
Once the circuits get that small....its gone beyond my ability.

 

[JCHarper]

A little update

Seems that it is only the miles display of the odometer. The kilometers display is correct, for actual miles. So looks like it's an IP issue more than likely.

 

[JCHarper]

update

Changed out the IP. Still has the issue. Still checking for a ground/short issue battery draw. Just haven't had that much time to deal with it. Also the metric side also does lose miles, but after the conversion is about 3k miles more than what the english odometer says. I saw it today while driving go from 102077 to 102064 so it does it while driving as well. A definite weird issue. Has to be a ground problem with the bcm/ccm to keep doing what it does. Anyway, it's an interesting issue and always looking for more ideas.