Code P0221 on 2002 BMW 525i

Hi
The Check Engine light just came on and the code I obtained from the OBD2 reader is P0221, "Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance Problem". The car has the M54 engine with auto trans, and a mere 20k miles.

Can you point me to the area where this malfunction might be (at the pedal or throttle body - or elsewhere. The "B" in the description is not very informative)? I'd also be interested if there is a process to eliminate this code as being a false indication, possibly masking some other root cause.
Thank you
Al