Patent ID: 8666639

Claim:
A fuel supply control apparatus for an engine provided with a fuel injection valve, a fuel pump for pumping fuel to the fuel injection valve and a fuel pressure sensor for detecting pressure of the fuel sent to the fuel injection valve, comprising: an engine control unit which controls the fuel injection valve; and a fuel pump control unit which controls the fuel pump, wherein the engine control unit receives an output signal from the fuel pressure sensor and outputs an actuating signal for the fuel pump to the fuel pump control unit, and receives a diagnostic signal output from the fuel pump control unit; the fuel pump control unit receives the actuating signal and outputs a manipulated variable of the fuel pump, and diagnoses whether or not abnormality occurs in input of the actuating signal, to output a signal indicating at least whether or not the abnormality occurs in the input of the actuating signal, as the diagnostic signal, to the engine control unit; and the engine control unit diagnoses whether or not abnormality occurs in input of the diagnostic signal, diagnoses based on the output signal from the fuel pressure sensor whether or not abnormality occurs in a control of the fuel pressure, judges based on the diagnostic signal whether or not the abnormality occurs in the input of the actuating signal in the fuel pump control unit, and performs a fail-safe function, based on whether or not the abnormality occurs in the input of the diagnostic signal, whether or not the abnormality occurs in the control of the fuel pressure, and further, whether or not the abnormality occurs in the input of the actuating signal in the fuel pump control unit.