Undefined Fuel-reserved For Proprietary Jun 2026

Flagging transactions that require specialized processing logic. 2. Why the "Undefined" Status Occurs

because the specific fuel type (and its associated tax rate) cannot be verified by the processing network. Why You See It POS Incompatibility undefined fuel-reserved for proprietary

Demystifying the "Undefined Fuel-Reserved for Proprietary" Error Why You See It POS Incompatibility Demystifying the

While less likely, “undefined fuel-reserved for proprietary” could refer to a in a controlled environment. If the user configures a but assigns no

Race cars and custom builds use ECUs from MoTeC, Haltech, or AEM. These allow user-defined fuel reserve logic. If the user configures a but assigns no fuel quantity to it, some firmware versions output undefined_fuel_reserved over CAN. When read by a generic dash display, it translates to the human-readable gibberish we see.

). These codes are reserved for vendors to define unique or proprietary products that do not fit into standard industry categories like regular gasoline or diesel. Squarespace Understanding Proprietary Fuel Codes