[ACR]

The speedometer quit and the po. changed it with a new one and now it registers about ten percent of the speed were traveling based on the gps . Where is the pickup coil located trans or axle? and where could I get one?

[Richard]

Hmmmmm, it is entirely possible that it is not calibrated properly. Google the manual for the VDO speedo, unless of course it was replaced with something else.

[Johnnyboy]

Depending on which speedometer you have it maybe simple. I had replaced one in the past, it was a VDO. All I had to do to program it was stop, push the button on the speedo to start. Drive exactly 1 mile and push the button again and it was done.

Just one way some are programmed, if it helps.

[ACR]

Yes it is a vdo. Were you able to put the actual miles on the new one?
The previous owner didn't say why he changed all the gages but if I could get it calibrated I would like to get the actual miles back on the odometer

[ACR]

Wow could it really be that easy.
I googled it and it looks quit simple but will be at the coach tomorrow to give it a go .

[Johnnyboy]

I do not think I was able to put the miles back to where the old was. I just keep the old one for record. When I programmed, I found a quiet street with the mile markers. Stopped right at the marker, drove around 45-55 mph to the next marker and pushed the button one more time.

Now that you have found the instructions, yes it’s that easy.

[Richard]

On the DDEC coaches, the total mileage is captured in the computer, in case there is a question. But, if the engine ECM has been changed then of course the mileage will be off.

[ACR]

Yes I did see the stored mileage on the Detroit display.Will see what I can do with it and keep my fingers crossed.

[folivier]

Think about this, if it's that easy to change the mileage on your new speedo to the correct total mileage, then what's to prevent someone from "rolling back" the mileage on his vehicle? Unless it can only be done once, but I doubt that.
Let us know what you find out.

[Fulltiming]

It is possible to get your speedometer set to a new mileage but I don't know the process they use and it is expensive. My speedometer didn't quit working, it went into hyperdrive. The odometer portion of the speedometer would begin to record miles anytime the key was turned on. Worse yet, it would add miles like you were traveling about 50 mph. I bought my speedometer, a VDO 437152 from Dicks Speedotach.com. They charged almost $500 for the speedometer with the mileage set to match my existing odometer. It has been several years but I believe I emailed a photo of my existing speedometer to them. They sent a new speedometer to me with the mileage of my existing speedometer. Probably wasn't a financially sound move but I preferred not to have the DMV records show an incorrect mileage reading on my records. At that time, I could have ordered the same VDO speedometer from Amazon for just about half the cost with the odometer reading 0 miles.

That speedometer does have a built in function to change the ratio used to correct for speed errors based on a measured mile as others have mentioned. That is easily changed at any time.