What causes the P0700 external request MIL light to illuminate?

[OMackenzie]

P0700 external request MIL light illumination indicates an engine malfunction. The reasons for engine malfunction are as follows: Fuel supply system malfunction: The fuel supply system mainly includes the fuel tank, fuel pump, pipelines, gasoline filter, carbon canister, carbon canister solenoid valve, fuel pressure regulator, fuel injectors, etc. Poor fuel quality: Fuel quality is the primary factor causing the engine malfunction light to illuminate. The anti-knock property of gasoline is represented by the octane number. The higher the octane number, the better the anti-knock property. For example, 97-octane gasoline has an octane number of not less than 97. Leaded gasoline can cause lead poisoning of the oxygen sensor. Therefore, poor fuel quality is the main reason for insufficient engine combustion, leading to the illumination of the engine malfunction light. Abnormal fuel pressure: If the fuel pump's supply pressure does not reach a certain level, it will result in poor atomization of the fuel injectors, thereby affecting the normal operation of the engine.