The OBD-II trouble code P0656 indicates a malfunction in the fuel level output circuit in the vehicle.
The fuel level output circuit is responsible for transmitting the fuel level signal to various vehicle systems, such as the instrument cluster, the powertrain control module (PCM), and the on-board diagnostics system. A malfunction in this circuit can cause a variety of issues, such as inaccurate fuel level readings, improper fuel level calculations by the PCM, and an illuminated fuel level warning light.
In order to diagnose and repair the issue, a qualified technician will need to use specialized diagnostic equipment to communicate with the vehicle's PCM and identify the root cause of the fuel level output circuit malfunction. The technician may need to test the wiring and connectors associated with the fuel level output circuit, as well as perform tests on the fuel level sensor itself.
Once the root cause of the issue is identified, the technician may need to repair or replace the wiring and connectors associated with the fuel level output circuit, or repair or replace the fuel level sensor if it is determined to be faulty.
It is important to address these issues promptly, as a malfunctioning fuel level output circuit can cause a variety of issues that may affect the drivability and safety of the vehicle. Inaccurate fuel level readings can lead to unexpected engine stalling, and an illuminated fuel level warning light can cause confusion and potentially distract the driver while driving.