Using the default HPT config for NGK AFX sensor, the scanner is showing 15.6 AFR in free air. I logged Raw Voltage and am showing 4.75 volts in free air. I set up the User Defined wideband config using V/.678 + 9 and now AFR in Scanner is showing 16 AFR in free air. Does anyone know what formula is being used in the default HPT config for this setup or should I not worry about it and use the default config anyway. TIA