I have a 2001 roadster 6-speed AMU Quattro that's producing a P0501 code (Vehicle Speed Sensor range/performance). What makes this really annoying is that MIL fails the state's emmission test. Here's the facts:
1. The Speedometer/Odometer operate normally. (I'm told they won't if the VSS is malfunctioning.)
2. The Cruise Control does NOT function. (I'm told the VSS signal is used by this system.)
3. The engine runs and revs normally. (I'm told it is limited to about 4K rpm if the VSS is malfunctioning.)
4. The vehicle-in-motion lock does NOT function. ( I'm told this is triggered by the central locking module via the VSS signal.)
5. The VSS was replaced at the suggestion of the local dealership. This had no effect except to lighten my wallet.
6. The Central Locking Module was replaced at the suggestion of the local dealership. This had no effect except to lighten my wallet to a greater extent.
7. All fuses are in working order.
8. The ECM relay and secondary air pump relay have been replaced.

The Bentley service manual is little help. The EWD's show the VSS signal carried on a bl/ws wire from the ECM to the instrument cluster. Then from the instrument cluster to the Central Locking Module. The Cruise control is not mentioned, so I'm guessing it's part of the nebulous Instrument cluster.

I'm guessing there's a wiring harness problem, but where to start?