Abstract: This disclosure includes systems and methods for calibrating a vehicle fuel gauge. Some systems include a fuel system processor that is configured to transmit a first signal and receive, from an ECM of the vehicle, a second signal that corresponds to a fuel level to be displayed on a gauge of the vehicle, and a fuel level interface circuit configured to receive the first signal and transmit a third signal that corresponds to the first signal to the ECM to cause the ECM to transmit the second signal, wherein the fuel system processor and/or the fuel level interface circuit are configured to calibrate the gauge such that a fuel level corresponding to the first signal matches the fuel level corresponding to the second signal.

Abstract: This disclosure includes systems and methods for testing a vehicle's fuel system. Some systems have a gauge configured to be mounted to a vehicle having a compressed gas fuel system including a compressed gas fuel tank, the gauge having a user interface configured to display fuel pressure within the fuel tank and receive user input to initiate diagnostic testing of the fuel system, and one or more processors configured to, in response to the user input, actuate one or more components of the fuel system, including a solenoid and/or a relay, and display, on the user interface, diagnostic information associated with the actuated one or more components.