What does it mean?
The fuel shut off solenoid is used to shut off the fuel supply to the fuel pump. It is typically controlled by the starter via a relay. When the ignition is off, the spring loaded plunger is in the down position, blocking fuel flow to the pump. When the starter is cranked, power is applied to the solenoid from the shut off relay. The plunger is then moved to up position, allowing fuel delivery to the pump.
When the ignition switch is released and the engine is running, low amperage current is applied to another winding on the solenoid to keep it in the up position. An example of a fuel shutoff valve control circuit Code P0007 stands for fuel shutoff valve control circuit high and indicates a problem with the shut off solenoid or its circuit.
Note: Circuit High Input codes are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that “leak” current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated.
Diagnosing a “high input” code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.