Toyota Avalon Service & Repair Manual: Fuel Pump Control Circuit

DESCRIPTION

The fuel pump (for low pressure side) circuit consists of the ECM, fuel pump (for low pressure side) and fuel pump control ECU (which operates the fuel pump (for low pressure side)). 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 control ECU. Based on the signal sent from the ECM, the fuel pump control ECU adjusts the fuel pump (for low pressure side) operation speed.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

INSPECT FUEL PUMP CONTROL ECU

*1

Fuel Pump Control ECU

-

-

(a) Remove the fuel pump control ECU.

Click here

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K15-1 (+B) - K15-3 (GND)

Always

200 Ω or higher

K15-1 (+B) - K15-2 (FPC)

Always

2 kΩ or higher

K15-2 (FPC) - K15-3 (GND)

Always

10 kΩ or higher

K14-1 (FPG) - K15-3 (GND)

Always

1 kΩ or higher

K14-2 (FPU) - K15-3 (GND)

Always

2 kΩ or higher

K14-3 (FPV) - K15-3 (GND)

Always

2 kΩ or higher

K14-4 (FPW) - K15-3 (GND)

Always

2 kΩ or higher

HINT:

This procedure checks for an internal short of the fuel pump control ECU when its transistor is stuck on.

NG

REPLACE FUEL PUMP CONTROL ECU

OK

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE OF FUEL PUMP CONTROL ECU)

*a

Front view of wire harness connector

(to Fuel Pump Control ECU)

(a) Disconnect the fuel pump control ECU connector.

(b) Turn the engine switch on (IG).

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

K15-1 (+B) - K15-3 (GND)

Engine switch on (IG)

11 to 14 V

HINT:

Make a note of the measured voltage as it may be used in a following Active Test.

NG

GO TO STEP 7

OK

3.

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

(a) Disconnect the fuel pump control ECU assembly 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

K15-2 (FPC) - A18-18 (FPC)

Always

Below 1 Ω

K15-2 (FPC) or A18-18 (FPC) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PUMP SINGLE PHASE ENERGIZATION)

*1

Fuel Pump Control ECU

-

-

(a) Disconnect the K14 fuel pump control ECU connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Active Test / Fuel Pump Single Phase Energization.

Powertrain > Engine > Active Test

Tester Display

Fuel Pump Single Phase Energization

(f) Operate the fuel pump control ECU 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

K14-2 (FPU) - Body ground

U Phase

4.4 to 8.4 V*

K14-3 (FPV) - Body ground

V Phase

4.4 to 8.4 V*

K14-4 (FPW) - Body ground

W Phase

4.4 to 8.4 V*

HINT:

  • *: This Active Test restricts the fuel pump control ECU assembly output duty cycle to 50%. Therefore, the output voltage of the fuel pump control ECU assembly will be approximately 50% of the power source voltage measured in a previous step.
  • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).

Result

Proceed to

The U phase, V phase and W phase are all normal

A

The U phase, V phase or W phase is abnormal

B

The U phase, V phase and W phase are all abnormal

C

B

REPLACE FUEL PUMP CONTROL ECU

C

GO TO STEP 6

A

5.

CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU - FUEL PUMP (FOR LOW PRESSURE SIDE))

(a) Disconnect the fuel pump control ECU connector.

(b) Disconnect the fuel pump (for low pressure side) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K14-2 (FPU) - K37-3 (BLPU)

Always

Below 1 Ω

K14-3 (FPV) - K37-4 (BLPV)

Always

Below 1 Ω

K14-4 (FPW) - K37-2 (BLPW)

Always

Below 1 Ω

K14-2 (FPU) or K37-3 (BLPU) - Body ground and other terminals

Always

10 kΩ or higher

K14-3 (FPV) or K37-4 (BLPV) - Body ground and other terminals

Always

10 kΩ or higher

K14-4 (FPW) or K37-2 (BLPW) - Body ground and other terminals

Always

10 kΩ or higher

HINT:

Perform "Inspection After Repair" after replacing the fuel pump (for low pressure side).

Click here

OK

REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

INSPECT ECM (FPC TERMINAL)

*a

Front view of wire harness connector

(to Fuel Pump Control ECU)

(a) Disconnect the fuel pump control ECU connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG).

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Active Test / Fuel Pump Single Phase Energization.

Powertrain > Engine > Active Test

Tester Display

Fuel Pump Single Phase Energization

(f) Operate the fuel pump control ECU using the Active Test function and measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Techstream Operation

Specified Condition

K15-2 (FPC) - Body ground

Before Active Test → During Active Test

Before Active Test: Resistance is stable → During Active Test: Resistance fluctuates*

HINT:

*: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the FPC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

OK

REPLACE FUEL PUMP CONTROL ECU

NG

REPLACE ECM

7.

CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF EFI-MAIN NO. 2 RELAY)

(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

3 (EFI-MAIN NO. 2 relay) - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 2 RELAY)

OK

8.

INSPECT EFI-MAIN NO. 2 RELAY

(a) Inspect the EFI-MAIN NO. 2 relay.

Click here

NG

REPLACE EFI-MAIN NO. 2 RELAY

OK

9.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - ECM)

(a) Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(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

2 (EFI-MAIN NO. 1 relay) - A18-46 (MREL)

Always

Below 1 Ω

2 (EFI-MAIN NO. 1 relay) or A18-46 (MREL) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

10.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 2 RELAY)

(a) Remove the EFI-MAIN NO. 1 and EFI-MAIN NO. 2 relays from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

5 (EFI-MAIN NO. 1 relay) - 2 (EFI-MAIN NO. 2 relay)

Always

Below 1 Ω

5 (EFI-MAIN NO. 1 relay) or 2 (EFI-MAIN NO. 2 relay) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

11.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND)

(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (EFI-MAIN NO. 2 relay) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

12.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - FUEL PUMP CONTROL ECU)

(a) Remove the EFI-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Disconnect the fuel pump control ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

5 (EFI-MAIN NO. 2 relay) - K15-1 (+B)

Always

Below 1 Ω

5 (EFI-MAIN NO. 2 relay) or K15-1 (+B) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

13.

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

(a) Disconnect the fuel pump control ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K15-3 (GND) - Body ground

Always

Below 1 Ω

OK

GO TO ECM POWER SOURCE CIRCUIT

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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