BMW E46 Limp Mode Due to Throttle Body Potentiometer Failure

The primary cause of WOT-induced limp mode is internal wear of the two potentiometers within the throttle body, leading to signal divergence. Confirm this by using diagnostic software to monitor 'Throttle Position' vs 'Pedal Position' in real-time during a test drive; the failure is confirmed if the DME logs an implausible signal or if the live data values 'cross' or drop out while the pedal is at 100% position. Ensure battery voltage is stable at 12.5V or higher during testing to rule out phantom communication faults.