Fuel Pump

FUEL PUMP

Description

The ECM activates the fuel pump for 1 second after the ignition switch is turned ON to improve engine startability. If the ECM receives a engine speed signal from the camshaft position sensor, it knows that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents battery discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It sends the control signal to the fuel pump control module, which in turn controls the fuel pump. System Description.







Component Function Check


1. CHECK FUEL PUMP FUNCTION

1.Turn ignition switch ON.





2.Pinch fuel feed hose (1) with two fingers.
Fuel pressure pulsation should be felt on the fuel feed
hose for 1 second after ignition switch is turned ON.

Is the inspection result normal?
YES- INSPECTION END
NO- Refer to Diagnosis Procedure.


Diagnosis Procedure


1. CHECK GROUND CONNECTION

1.Turn ignition switch OFF.
2.Check ground connection M95. Refer to Ground Inspection in Circuit Inspection.
Is the inspection result normal?
YES- GO TO 2.
NO- Repair or replace ground connection.

2. CHECK FPCM POWER SUPPLY CIRCUIT

1.Turn ignition switch OFF.
2.Disconnect FPCM harness connector.
3.Turn ignition switch ON.
4.Check the voltage between FPCM harness connector and ground.





Is the inspection result normal?
YES- GO TO 4.
NO- GO TO 3.

3. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors B3, E121
- 15 A fuse (No.41)
- Harness for open or short between FPCM and IPDM E/R
- Repair open circuit, short to ground or short to power in harness or connectors.

4. CHECK FPCM GROUND CIRCUIT FOR OPEN AND SHORT

1.Turn ignition switch OFF.
2.Check the continuity between FPCM harness connector and ground.





3.Also check harness for short to power.
Is the inspection result normal?
YES- GO TO 5.
NO- Repair open circuit or short to power in harness or connectors.

5. CHECK FPCM INPUT AND OUTPUT CIRCUITS FOR OPEN AND SHORT

1.Disconnect ECM harness connector.
2.Check the continuity between FPCM harness connector and ECM harness connector.





3.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 7.
NO- GO TO 6.

6. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors B1, M7
- Harness for open or short between FPCM and ECM
- Repair open circuit, short to ground or short to power in harness or connectors.

7. CHECK FUEL PUMP CONTROL CIRCUIT FOR OPEN AND SHORT

1.Disconnect "fuel level sensor unit and fuel pump (main)" harness connector.
2.Check the continuity between FPCM harness connector and "fuel level sensor unit and fuel pump (main)"
harness connector.





3.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 8.
NO- Repair open circuit, short to ground or short to power in harness or connectors.

8. CHECK FUEL PUMP

.
Is the inspection result normal?
YES- GO TO 9.
NO- Replace fuel pump. Exploded View.

9. CHECK FPCM

P1220.
Is the inspection result normal?
YES- GO TO 10.
NO- Replace FPCM.

10. CHECK INTERMITTENT INCIDENT

Intermittent Incident.
- INSPECTION END


Component Inspection


1. CHECK FUEL PUMP

1.Turn ignition switch OFF.
2.Disconnect "fuel level sensor unit and fuel pump (main)" harness connector.
3.Check resistance between "fuel level sensor unit and fuel pump (main)" terminals as follows.





Is the inspection result normal?
YES- INSPECTION END
NO- Replace "fuel level sensor unit and fuel pump (main)". Removal and Installation.