fireman

When I am cruising around and click my Scanmaster over to MPH, it reads like 24mph when I am going like 60mph. Whats weird is my speedo is accurate.
I would imagine the Scanmaster pulls its info form the PCM, which pulls the speed info from the sensor on the trans.

thoughts?

Guest47904

Let's ad more confusion. The VSS sends it's signal to the PCM which inturn sends it out to the instrument cluster to signal the speedo too. Figure that one out.

fireman

Injuneer?

I might try and call the Scanmaster people today and see if they have any info..

Injuneer

I can't figure it out. It would almost indicate that the VSS was putting out a 17 pulse/rev signal used in an M6, but the PCM was programmed for the 40 pulse/rev signal produced by the A4, and someone had inserted a signal converter like the Dakota Digital unit between the PCM and the speedo.

Wrong forum.

fireman

I think my PCM may have an auto tune in it. I know that it throws a couple DTCs that are related to an auto trans.
There certainly is no converter of any kind in there. I also have 2 different instrument clusters and the result is the same with both.
It'll be Monday before I can ask the Scanamster people.

Injuneer

The converter would not be in the instrument cluster. It would be in the wire for the speedo, that runs from the PCM to the panel.

fireman

Hmm, no converter there either.

very strange