Odometer Rollback kinda sorta
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Le Mans Master
Joined: Dec 2004
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Odometer Rollback kinda sorta
I've seen a few threads pop up over the years questioning mileage on cars for sale. Threads on how to tell if the odometer was "rolled back"
I had to fix a minor transmission leak on my own car which got me to thinking what would happen if you just unplugged the vss ? Without the vss plugged in would the miles still add up ? I had a Ford that the speedo cable snapped on and when it did the odometer stopped working along with the speedometer. I've seen quite a few super low mile C4's for sale and this might explain it
I had to fix a minor transmission leak on my own car which got me to thinking what would happen if you just unplugged the vss ? Without the vss plugged in would the miles still add up ? I had a Ford that the speedo cable snapped on and when it did the odometer stopped working along with the speedometer. I've seen quite a few super low mile C4's for sale and this might explain it
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Le Mans Master
Joined: Dec 2004
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Race Director
Joined: May 2006
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From: Phoenix Arizona
Computer controled engines use the vss for computing, so various problems (spark adv. etc. depending upon model) can occur if you disconnect it. As long as people well pay for low mileage, there are people out there that will supply it! The other thing, the newer the corvette more likely the older the owner. The older the owner, the less they are driven. And no, putting the car on jackstands won't do it. (how many hours does it take to go 30,000 miles at 80mph?)
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Le Mans Master
Joined: Dec 2004
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I know your not going to roll the miles off with the car on stands.
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Le Mans Master
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Race Director
Joined: Jan 2005
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From: Slidell Louisiana
On a related note when I did my gear swap I programed in the 3.45s via tuner cat while the 2.59s were still installed and my car threw some codes on the short drive to the autoshop.
Mike
Mike
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Team Owner
Joined: Dec 2000
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From: Phila., PA burbs
I can't comment on other years, but I can tell you on a 91 the car will not go into "limp home mode". I had the shaft in the VSS snap on my car and other than no speedo/odometer the car ran as it should. It did display a trouble code, though (code 24 if I recall correctly). As a matter of fact, it happened on the way to the track and I ran it anyway. Times were exactly where they were with a functioning VSS. 
So buyers beware when I sell my car someday, it probably has 120,660 miles instead of the 122,600 displayed
So buyers beware when I sell my car someday, it probably has 120,660 miles instead of the 122,600 displayed
Safety Car
Joined: May 2002
Posts: 4,010
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From: Somewhere nowhere
on the 96 impala ss, u just pull the correct fuse, and it stops counting mileage. no impala owners will talk about it, but everyone knows it. the fuse is labled A/C, but it really controls the digital odometer.
I never tried it on my C4. maybe one day I should go through all the fuses one by one.
I never tried it on my C4. maybe one day I should go through all the fuses one by one.
Elite Torch Red Member
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My buddy had an '86 Fiero, we disconnected some plug(not sure which) but it disabled the speedo and odo. He did it with 33,000 miles since the warranty was still good for another two years. Anytime he brought it in for warranty work(which was often) he would plug it back in. One time he forgot and the tech did some kind of check(maybe he was just BSing us) and said there was over 100,000 miles on the car, the warranty was now void. Dealer said, pay up sucker!
Safety Car
Joined: May 2003
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From: Houston Texas
I think the mileage is stored in the CCM. So if you buy a CCM from a car with less mileage and stick it in yours, the lower mileage will be displayed. If you buy a new CCM you will start with 0 miles.
Le Mans Master
Joined: Apr 2005
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From: Scarborough ONTARIO
Never trust mileage on pre 91 cars, infact if u want to stop odo, than pull the dash cluster turn over and put it on a table, there are 2 wires goes to odo u just need to unlug it, thats what somebody explained to me, now u cant do the same way later than 91 vettes. Dont count on me as some guy told me at vette show. My next vette got to be later 91 or only project only vettes from pre 91.
Safety Car
Joined: Feb 1999
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From: Mexico Beach FL
Therefore, if the CCM was swapped and is scanned with a scan-tool, it will tell you that the CCM is not for that car.
In addition, the CCM stores the option content of the vehicle (like the C68 climate control), and the CCM, being the master computer, controls the communications with those options.
If the CCM does not know those options exist, it won't attempt to communicate with them.
Tom Piper
