Why would my speed read correctly but my scanmaster read lower, for example my speedo reads 70 the scanmaster will read 29 or so, if the speedo reads 100 the scanmaster may read 40.

Any ideas? The car did have a auto to m6 swap done before I got it, but since then i have put in a m6 engine wiring harness, now instead of using the vss hook up that the guy who did the swap added, i use the one from the new harness, BUT they both do the same thing, the speedo reads fine the scanmaster doesnt.

any help is appriciated.

Thanks
Patrick

 

The tune is most likely not set up correctly.

 

Uh, ok, but bone stock tune, I've tried three different stock M6 tunes, they all do the same thing.

Thanks for the advice tho
Patrick