Fuel Pump Control Circuit

2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pump Control Circuit

Fuel Pump Control Circuit

DESCRIPTION

The fuel pump circuit consists of the ECM, fuel pump and fuel pump ECU (which operates the fuel pump). Based on the engine output, the ECM determines the fuel pump speed. The speed is then converted to a duty signal and sent to the fuel pump ECU. Based on the signal sent from the ECM, the fuel pump ECU adjusts the fuel pump operation speed between 3 settings.

WIRING DIAGRAM





INSPECTION PROCEDURE

This troubleshooting procedure is based on the premise that the engine is started. If the engine is not started, proceed to the problem symptoms table (Symptom Related Diagnostic Procedures).

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PUMP)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON and turn the Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.
(d) Check whether operating sounds can be heard while operating the fuel pump using the Techstream.
OK:
Operating sounds can be heard from fuel pump.
NG -- INSPECT CIRCUIT OPENING RELAY (C/OPN)
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM AND BODY GROUND)





(a) Disconnect the R7 fuel pump ECU connector.
(b) Disconnect the A24 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. REPLACE FUEL PUMP ECU
(a) Replace the fuel pump ECU (Removal)

NEXT -- Continue to next step.
4. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
(a) Check the fuel pump operation.
OK:
Malfunction has been repaired successfully.
NG -- REPLACE ECM
OK -- END
5. INSPECT CIRCUIT OPENING RELAY (C/OPN)





(a) Remove the circuit opening relay (C/OPN) from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPLACE CIRCUIT OPENING RELAY (C/OPN)
OK -- Continue to next step.
6. INSPECT CIRCUIT OPENING RELAY (POWER SOURCE VOLTAGE)





(a) Remove the circuit opening relay (C/OPN) from the engine room relay block.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





NG -- CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - IGN FUSE AND INTEGRATION RELAY)
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - ECM AND FUEL PUMP ECU)





(a) Remove the circuit opening relay (C/OPN) from the engine room relay block.
(b) Disconnect the A24 ECM connector.
(c) Disconnect the R7 fuel pump ECU connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (FUEL PUMP - FUEL PUMP ECU)





(a) Disconnect the R6 fuel pump connector.
(b) Disconnect the R8 fuel pump ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT FUEL PUMP
(a) Inspect the fuel pump. Fuel Pump Control Circuit
NG -- REPLACE FUEL PUMP
OK -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM AND BODY GROUND)





(a) Disconnect the R7 fuel pump ECU connector.
(b) Disconnect the A24 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
11. REPLACE FUEL PUMP ECU
(a) Replace the fuel pump ECU (Removal)

NEXT -- Continue to next step.
12. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
(a) Check the fuel pump operation.
OK:
Malfunction has been repaired successfully.
NG -- REPLACE ECM
OK -- END
13. CHECK HARNESS AND CONNECTOR (CIRCUIT OPENING RELAY (C/OPN) - IGN FUSE AND INTEGRATION RELAY)





(a) Remove the circuit opening relay (C/OPN) from the engine room relay block.
(b) Remove the IGN fuse from the engine room relay block.
(c) Remove the integration relay from the engine room relay block.
(d) Disconnect the 1B integration relay connector.
(e) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- GO TO ECM POWER SOURCE CIRCUIT