Fuel Pump: Testing and Inspection

Fuel Pump Circuit Check

Description

System Description





*: ECM determines the start signal status by the signals of engine speed and battery voltage.

The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start ability. If the ECM receives a engine speed signal from the camshaft position sensor (PHASE), 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 controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.






Component Description

A turbine type design fuel pump is used in the fuel tank.






Diagnosis Procedure

1. CHECK OVERALL FUNCTION

1 Turn ignition switch ON.
2 Pinch fuel feed hose with two fingers.





Fuel pressure pulsation should be felt on the fuel feed hose for 1 second after ignition switch is turned ON.

OK or NG
OK
INSPECTION END
NG
GO TO 2.

2. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I

1 Turn ignition switch OFF.
2 Disconnect ECM harness connector.
3 Turn ignition switch ON.
4 Check voltage between ECM terminal 113 and ground with SDT or tester.











OK or NG
OK
GO TO 5.
NG
GO TO 3.

3. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II

Check voltage between IPDM E/R terminal 46 and ground with SDT or tester.











OK or NG
OK
GO TO 4.
NG
GO TO 12.

4. DETECT MALFUNCTIONING PART

Check harness for open or short between IPDM E/R and ECM


Repair harness or connectors.

5. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-III

1 Turn ignition switch OFF.
2 Reconnect all harness connectors disconnected.
3 Disconnect "fuel level sensor unit and fuel pump" harness connector.





4 Turn ignition switch ON.
5 Check voltage between "fuel level sensor unit and fuel pump" terminal 1 and ground with SDT or tester.











6 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 9.
NG
GO TO 6.

6. CHECK 15 A FUSE

1 Turn ignition switch OFF.
2 Disconnect 15 A fuse.
3 Check 15 A fuse (No.48).

OK or NG
OK
GO TO 7.
NG
Replace 15 A fuse.

7. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-IV

1 Disconnect IPDM E/R harness connector E119.
2 Check harness continuity between "fuel level sensor unit and fuel pump" terminal 1 and IPDM E/R terminal 13.
Refer to Wiring Diagram.






3 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 12.
NG
GO TO 8.

8. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors C1, E41
- Harness for open or short between "fuel level sensor unit and fuel pump" and IPDM E/R


Repair open circuit or short to ground or short to power in harness or connectors.

9. CHECK FUEL PUMP GROUND CIRCUIT FOR OPEN AND SHORT

1 Check harness continuity between "fuel level sensor unit and fuel pump" terminal 3 and ground.
Refer to Wiring Diagram.






2 Also check harness for short to ground.

OK or NG
OK
GO TO 11.
NG
GO TO 10.

10. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors C1, E41
- Harness for open or short between "fuel level sensor unit and fuel pump" and ground


Repair open circuit or short to power in harness or connectors.

11. CHECK FUEL PUMP

Refer to "Component Inspection".

OK or NG
OK
GO TO 12.
NG
Replace fuel pump. Refer to [Fuel Level Sensor Unit, Fuel Filter and Fuel Pump Assembly: Removal and Installation] Removal and Replacement.

12. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.

OK or NG
OK
Replace IPDM E/R. Refer to [IPDM E/R: Removal and Installation of IPDM E/R] Service and Repair.
NG
Repair or replace harness or connectors.

Component Inspection

Fuel Pump

1) Disconnect "fuel level sensor unit and fuel pump" harness connector.
2) Check resistance between "fuel level sensor unit and fuel pump" terminals 1 and 3.