The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.
The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel pump module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel pump module. The function of the venturi pump is to fill the fuel pump module reservoir. The fuel pressure regulator, a part of the fuel pump module, maintains the correct fuel pressure to the fuel injection system. The fuel pump module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.
Step | Action | Values | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||
2 |
Important: Inspect the fuel system for damage or external leaks before proceeding with this diagnostic.
Does the fuel pump operate? | -- | Go to Step 3 | |||||
3 |
Important: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
Important:
Is the fuel pressure within the specified range? | 345-414 kPa (50-60 psi) | Go to Step 4 | Go to Step 8 | ||||
4 |
Important: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gage for one minute. Does the fuel pressure decrease by more than the specified value? | 34 kPa (5 psi) | Go to Step 7 | Go to Step 5 | ||||
5 |
Does the fuel pressure decrease by more than the second specified value? | 69 kPa (10 psi) 14 kPa (2 psi) | Go to Step 13 | Go to Step 6 | ||||
6 |
Does the scan tool parameters indicate a lean condition? | -- | Go to Step 10 | |||||
7 |
Does the fuel pressure remain constant? | -- | Go to Step 13 | Go to Step 12 | ||||
8 | Is the fuel pressure more than the specified value? | 414 kPa (60 psi) | Go to Step 9 | Go to Step 10 | ||||
9 | Inspect the return side of the fuel filter for a restriction. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||
10 | Inspect the following components for a restriction:
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 | ||||
11 | Inspect the harness connectors and the ground circuits of the fuel pump for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||
12 |
Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
13 | Replace the fuel pump module. Refer to Fuel Pump Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
14 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 3 |