Idle Switch failure Error Code 2121

[Michael Hopton]

Does the idle switch fail often on the 3B, similar to the WOT/idle switch on the 10vt engines?
I ask becuase I am getting the code but the switch seems to be set correctly but after
driving for 5 minutes in stop and go traffic I get the check engine code? Any recommendations
for a source of the switches, Bosch dealer perhaps?

thanks and regards, Mike Hopton