Hi Gary,

Having checked the wiring diagram, it looks like the Vehicle speed is proccessed by the ABS and output from the ABS module at pin 25 on a blue/red wire to the engine ECU pin B41 which also splices off to a multiplug on n/s/f inner wing/bulkhead area whci takes the VSS to the cluster and other components like radio and info display.

If the cluster is reading Vehicle speed then I would expect a signal is being output from ABS and is being corrupted on its way to engine ECU so compare signal at abs pin 25 with ECU pin B41,

Post the images if you can.

Mike