Chart A6 - Fuel System Diagnosis

NOTE: The following step numbers refer to the step numbers in the accompanying Flow Chart.

5) This step checks relay ground circuit No. 450.
6) This step checks ECM control of relay through circuit 465.
7) The fuel pump circuit includes an engine oil pressure switch. If fuel pump relay fails, the fuel pump will continue to run via oil pressure switch circuit. Relay failure will result in extended cranking times and possible no start condition.
8) This test checks the oil pressure switch to be sure it provides battery feed to fuel pump if pump relay fails.
9) This test checks for open oil pressure switch with ignition "OFF". Should switch stick closed, fuel pump will continue to run and discharge battery.

Fig 1: Chart A6 Schematic, Fuel System Diagnosis

Fig 2: Flow Chart A6, Fuel System Diagnosis

From Chart A-5

Fig 3: Flow Chart A6, Fuel System Diagnosis (2 Of 2)