P2137 - Throttle Position Sensor - error

[exec406]

Anyone get this fault? I keep getting it intermittently. I can clear it with an ELM OBD2 adapter and the Torque Pro app but it always returns at varying frequencies. It's described as this:

Throttle/Pedal Position Sensor/Switch "B" / "C" Voltage Correlation

A while ago, I took the car (a 2003 406 D9 saloon 2.2 Hdi) to the main dealer who fitted part: P00001920AK (Sensor pedal). The old part was taken in part exchange.

Anyone any ideas on what the fix to this could be? Car goes into limp home mode each time, eventually I get the engine power back if I don't clear it with the ELM interface.

Thanks