Toyota Tundra Service Manual: 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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP/SPEED)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump/Speed.

(e) Check whether operating sounds can be heard while operating the fuel pump using the Techstream.

OK:

Operating sounds can be heard from fuel pump.

Result

Result

Proceed to

NG

A

OK

B

B

GO TO STEP 13

A

2.

INSPECT FUEL PUMP ECU (POWER SOURCE VOLTAGE)

(a) Disconnect the fuel pump ECU connector.

(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

R11-6 (+B) - Body Ground

Ignition switch ON

11 to 14 V

NG

GO TO STEP 9

OK

3.

CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - BODY GROUND)

(a) Disconnect the fuel pump ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

R11-3 (E) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

CHECK HARNESS AND CONNECTOR (FUEL PUMP - FUEL PUMP ECU)

(a) Disconnect the fuel pump connector.

(b) Disconnect the fuel pump ECU connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

R6-4 (B) - R11-1 (FP)

Always

Below 1 Ω

R6-5 (E) - R11-2 (FP-)

Always

Below 1 Ω

R6-4 (B) or R11-1 (FP) - Body ground

Always

10 kΩ or higher

R6-5 (E) or R11-2 (FP-) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.

INSPECT FUEL PUMP

(a) Inspect the fuel pump (See page ).

HINT:

Perform "Inspection After Repair" after replacing the fuel pump (See page ).

NG

REPLACE FUEL PUMP

OK

6.

CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM)

(a) Disconnect the fuel pump ECU connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

R11-5 (FPC) - A24-52 (FPC)

Always

Below 1 Ω

R11-5 (FPC) or A24-52 (FPC) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

REPLACE FUEL PUMP ECU

(a) Replace the fuel pump ECU (See page ).

NEXT

8.

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Check the fuel pump operation.

OK:

Malfunction has been repaired successfully.

OK

END

NG

REPLACE ECM

9.

INSPECT FUEL PUMP RELAY (F/PMP)

(a) Inspect the fuel pump relay (F/PMP) (See page ).

NG

REPLACE FUEL PUMP RELAY (F/PMP)

OK

10.

CHECK FUEL PUMP RELAY (F/PMP) (POWER SOURCE VOLTAGE)

(a) Remove the fuel pump relay (F/PMP) 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:

Tester Connection

Condition

Specified Condition

F/PMP relay (1) - Body ground

Ignition switch ON

11 to 14 V

F/PMP relay (5) - Body ground

Always

11 to 14 V

NG

GO TO STEP 12

OK

11.

CHECK HARNESS AND CONNECTOR (FUEL PUMP RELAY - FUEL PUMP ECU)

(a) Remove the fuel pump relay (F/PMP) from the engine room relay block.

(b) Disconnect the fuel pump ECU connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

F/PMP relay (3) - R11-6 (+B)

Always

Below 1 Ω

F/PMP relay (3) or R11-6 (+B) - Body ground

Always

10 kΩ or higher

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (FUEL PUMP RELAY - BODY GROUND)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.

CHECK HARNESS AND CONNECTOR (FUEL PUMP RELAY - INTEGRATION RELAY, BATTERY AND BODY GROUND)

(a) Disconnect the cable from the battery negative (-) terminal.

(b) Disconnect the cable from the battery positive (+) terminal.

(c) Remove the fuel pump relay (F/PMP) from the engine room relay block.

(d) Remove the integration relay from the engine room relay block.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

F/PMP relay (1) - 2B-4

Always

Below 1 Ω

F/PMP relay (5) - Battery positive (+) terminal

Always

Below 1 Ω

F/PMP relay (2) - Body ground

Always

Below 1 Ω

F/PMP relay (1) or 2B-4 - Body ground

Always

10 kΩ or higher

F/PMP relay (5) or Battery positive (+) terminal - Body ground

Always

10 kΩ or higher

OK

GO TO ECM POWER SOURCE CIRCUIT

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

13.

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE FUEL PUMP)

(a) Remove the fuel tank assembly (See page ).

(b) Remove the fuel pump from the fuel tank assembly.

(c) Clean the fuel pump to completely remove any remaining fuel.

(d) Connect the fuel pump connector.

CAUTION:

Confirm that no fuel remains inside or on the outside of the fuel pump.

(e) Connect the Techstream to the DLC3.

(f) Turn the ignition switch to ON.

(g) Turn the Techstream on.

(h) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump Duty.

(i) Operate the fuel pump using the active test function and measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Techstream Operation

Specified Condition

1 - 2

FPC Duty: 25%

3.2 to 4.05 V

FPC Duty: 80%

8.8 to 12.5 V

(j) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump/Speed.

(k) Operate the fuel pump using the active test function and measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Techstream Operation

Specified Condition

1 - 2

ON (FPC Duty: 90%)

9.0 to 14.0 V

HINT:

  • Be sure to measure the voltage with all of the connectors connected.
  • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).
NG

GO TO STEP 16

OK

14.

CHECK HARNESS AND CONNECTOR (FUEL PUMP ECU - ECM)

(a) Disconnect the fuel pump ECU connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

R11-5 (FPC) - A24-52 (FPC)

Always

Below 1 Ω

R11-5 (FPC) or A24-52 (FPC) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

15.

REPLACE FUEL PUMP

(a) Replace the fuel pump (See page ).

HINT:

Perform "Inspection After Repair" after replacing the fuel pump (See page ).

NEXT

GO TO STEP 17

16.

REPLACE FUEL PUMP ECU

(a) Replace the fuel pump ECU (See page ).

NEXT

17.

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Check the fuel pump operation.

OK:

Malfunction has been repaired successfully.

OK

END

NG

REPLACE ECM

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