Electronic throttle twist grip potentiometer channel 1 signal implausible or voltage out of calibrated range.
Yellow triangle warning and 'E-Gas Fault' on TFT display; engine enters limp-home mode with maximum throttle restricted to 30%.
Connect diagnostic scanner (BMW ISTA/D or GS-911). Read live sensor voltage channel A: closed throttle specification is 0.75 – 0.85 V; wide open throttle must reach 4.10 – 4.30 V. Channel B must read exactly half the voltage of channel A across the full rotation. If synchronization deviates >5%, replace twist grip sensor.
- Contamination or moisture inside twist grip sensor housing
- Severed CAN-Bus wire inside handlebar switch harness
- Grip assembly misaligned after installing aftermarket handguards
Inspect throttle grip housing for binding against bar-end weights. Perform E-Gas twist grip adaptation calibration via diagnostic tool. Replace throttle control unit if Hall sensor fails sync.