Fuel Pump Control Circuit

SYSTEM DESCRIPTION

System Relational Diagram:

Operational Description:

Fuel Pump ON-OFF Control
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start-up. If the ECM receives a 1 signal from the camshaft position sensor, it knows that the engine is rotating, and causes the pump to activate. If the 1 signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents the battery from discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.

SYSTEM INSPECTION PROCEDURE

Circuit Diagram:

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

COMPONENT INSPECTIONS

View: Fuel Pump Relay:

Continuity Chart:

Fuel Pump Relay
Check continuity between terminals (3) and (5).
If NG, replace relay.

View: Test Connections:

Fuel Pump
1. Disconnect fuel pump harness connector.
2. Check resistance between terminals (1) and (3).

Resistance: 0.2 - 5.0 ohms at 20°C (68°F)

If NG, replace fuel pump.

View: Fuel Pump Control Module (FPCM):

View: Test Connections:

Fuel Pump Control Module

CAUTION:
- Be sure to ground the fuel pump control module (FPCM) body before inspection.

1. Turn off engine and disconnect fuel pump control module harness connector.
2. Connect proper wires between the fuel pump control module harness terminals.
3. Start engine and check voltage between terminal (7) and terminal (4) on fuel pump control module.
If NG, replace fuel pump control module.