P0313 indicates that the engine control module has detected a misfire that occurs specifically when the fuel tank is low. This code is designed to differentiate a misfire caused by fuel starvation from other types of misfires, though it often points to a failing fuel pump that struggles when fuel volume drops.
The most literal cause; operating the vehicle with an extremely low fuel tank can cause the pump to draw in air, leading to a lean misfire.
A failing fuel pump often struggles to maintain adequate pressure when the tank is low, as it loses the cooling and pressure assistance from the weight of the surrounding fuel.
A restricted fuel filter limits flow, which becomes critically apparent when the pump is already struggling to draw from a low tank.
A malfunctioning fuel gauge sending unit may incorrectly report low fuel to the engine computer, triggering the low-fuel misfire logic unnecessarily.
Extremely rare; the PCM would have to internally fail in a way that falsely triggers the low fuel misfire monitor, which is highly uncommon.
It is not recommended. A misfire can cause unburned fuel to enter the catalytic converter, which can overheat and destroy it, leading to costly repairs.
Sometimes, yes. If you were driving on a very low tank, refueling and clearing the code might fix it. However, it often indicates a weak fuel pump that only fails when the tank is low.
No, replacing the engine computer is almost never the correct fix for P0313. The PCM is simply doing its job by reporting a misfire under low fuel conditions; the actual cause is almost always a mechanical fuel delivery issue, not a faulty computer.
Fuel pumps rely on the surrounding fuel for cooling and to assist with inlet pressure. When the tank is low, a worn pump can cavitate or fail to maintain pressure, causing a lean misfire.