Fuel Pump Control Circuit

1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pump Control Circuit

Fuel Pump Control Circuit

DESCRIPTION

The fuel pump is operated by the ECM according to the vehicle running condition. After the ECM receives the engine start requirement signal from the HV control ECU, an NE signal comes in immediately when the engine is cranked by MG1 (basically, the fuel pump can operate while the NE signal is generated).
The ECM grounds the FC terminal line after receiving NE signal. It causes to energize the coil in the circuit opening relay, and the current flows to the fuel pump.
When the signal to stop the engine comes from the HV control ECU to the ECM, or when the fuel cut operation is performed such as decelerating by the engine brake, the fuel pump is stopped.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CIRCUIT OPENING RELAY)
(a) Connect Techstream to the DLC3.
(b) Turn the power switch ON (IG).
(c) Turn the tester ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.
(e) Check the relay operation while operating it with the tester.
OK:
Operating noise can be heard from the relay.
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

2. INSPECT POWER SOURCE CIRCUIT
NG -- REPAIR OR REPLACE POWER SOURCE CIRCUIT COMPONENTS
OK -- Continue to next step.

3. INSPECT INTEGRATION RELAY (C/OPN RELAY)




(a) Remove the integration relay from the engine room relay block.
(b) Inspect the C/OPN relay.
Standard resistance:





(c) Reinstall the integration relay.
NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

4. CHECK ECM (FC VOLTAGE)




(a) Turn the power switch ON (IG).
(b) Measure the voltage between the specified terminals of the E5 and E6 ECM connectors.
Standard voltage:






OK -- INSPECT FUEL PUMP
NG -- CHECK AND REPAIR HARNESS AND CONNECTOR
5. INSPECT FUEL PUMP




(a) Disconnect the F14 fuel pump connector.
(b) Inspect the fuel pump resistance.
(1) Measure the resistance between terminals 3 and 7.
Standard resistance:





(c) Inspect the fuel pump operation.
(1) Apply battery voltage to the fuel pump terminals.
Check that the pump operates.
NOTICE:
- These tests must be done quickly (within 10 seconds) to prevent the coil from burning out.
- Keep fuel pump as far away from the battery as possible.
- Always do the switching at the battery side.
(d) Reconnect the fuel pump connector.
NG -- REPAIR OR REPLACE FUEL TANK ASSEMBLY
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP, FUEL PUMP - BODY GROUND)
(a) Check the harness and the connectors between the circuit opening relay and the fuel pump connector.





(1) Remove the integration relay from the engine room relay block.
(2) Disconnect the F14 fuel pump connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):






(4) Reinstall the integration relay.
(5) Reconnect the fuel pump connector.
(b) Check the harness and the connectors between the fuel pump connector and the body ground.





(1) Disconnect the F14 fuel pump connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






(3) Reconnect the fuel pump connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM