F.CAL: Payload Meter Won't Calibrate The most common cause for failure to calibrate is a missing speed signal to the payload meter. Check the inputs to the payload meter to confirm that the speed signal is being received. Refer to “Monitoring Input Signals”. The payload meter also uses the R-terminal and oil pressure signals for calibration. These signals indicate that the engine is running. Verify these signals are being properly received. M20-42 Payload Meter II™ Troubleshooting M20007.2 3/02