Toyota Tundra (2015 year). Manual — part 1691

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(a) Check the fuel pump control circuit

.

NOTICE:

Check the fuel pump control circuit and proceed to the next step.

HINT:

The fuel pump ECU changes the fuel pump drive voltage between high, middle, and low. The fuel pump
is regulated at a voltage consistent with the fuel consumption amount.
The fuel pump ECU changes the drive voltage to high when starting the engine and during heavy loads,
and low when the engine is idling.

4.

PERFORM ACTIVE TEST USING TECHSTREAM (FUEL PRESSURE SWITCHING
VALVE)

(a) Install the pressure gauge

.

HINT:

In order to reduce the rise in fuel temperature, open the hood during the inspection.

(b) Chock the wheels.

(c) Securely apply the parking brake.

(d) Warm up the engine until the engine coolant temperature is 75°C (167°F) or more.

(e) Connect the Techstream to the DLC3.

(f) Allow the engine to idle and turn the A/C on (MAX COOL, blower motor on maximum setting).

(g) Depress the brake pedal and move the shift lever to D.

HINT:

When checking the fuel pressure, it is okay if the shift lever is in N or the air conditioner is off.

(h) Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Fuel

Pressure Switching Valve / All Data / Short FT #1 and Short FT #2.

(i) Using the Active Test, switch the fuel pressure switching valve to "High" and "Low".

(j) Check the change in Short FT and the fuel pressure.

HINT:

When performing the Active Test, wait approximately 20 seconds for the Short FT value to stabilize.

Result

RESULT

CONDITION

PROCEED

TO

Short FT change is below 7% and fuel pressure does not

change 30 kPa or more

Performing switching between

"High" and "Low"

A

Anything except above

Performing switching between

"High" and "Low"

B

HINT:

3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pressur...

A

When normal:

CHANGE IN SHORT FT WHILE PERFORMING ACTIVE TEST

10 TO 20%

Active Test State

Low

High

Normal Fuel Pressure

270 to 330 kPa

370 to 430 kPa

Reference values when performing Active Test (E85 Fuel):

Data List

Low

High

AFS Voltage B1 S1

3.23 V

3.10 V

AFS Voltage B2 S1

3.26 V

3.05 V

O2S B1 S2

0.11 V

0.33 V

O2S B2 S2

0.13 V

0.21 V

Short FT #1

11.7%

-16.5%

Long FT #1

-2.4%

-2.4%

Short FT #2

11.7%

-16.5%

Long FT #2

-2.4%

-2.4%

AF Lambda B1 S1

0.99

0.96

AF Lambda B2 S1

1.00

0.96

Alcohol Density Estimate

73%

73%

Alcohol Density Learning

Compl

Compl

When malfunctioning:

CHANGE IN SHORT FT WHILE PERFORMING ACTIVE TEST

LESS THAN 7%

7% OR MORE

ACTIVE TEST STATE

LOW

HIGH

LOW

HIGH

Fuel pressure when there is fuel leak from fuel pipes

Below 270

kPa

Below 370

kPa

Below 270

kPa

Below 370

kPa

Fuel pressure when fuel pressure in high pressure side

pressure regulator cannot remain stable

Below 270

kPa

Below 370

kPa

Below 270

kPa

Below 370

kPa

Fuel pressure when fuel pump ECU is malfunctioning and

drive voltage stuck at low

270 to 330

kPa

Below 370

kPa

-

-

Fuel pressure when fuel pump ECU is malfunctioning and

drive voltage stuck at high

370 kPa or

higher

370 to 430

kPa

-

-

Fuel pressure when fuel pressure switching valve stuck

No change in pressure

-

-

Fuel pressure when fuel pressure in low pressure side

pressure regulator cannot remain stable

-

-

Below 270

kPa

370 to 430

kPa

Fuel pressure when fuel pump discharge ability decreases

-

Below 370

kPa

-

Below 370

kPa

B

REPLACE FUEL SUCTION WITH PUMP AND GAUGE

TUBE ASSEMBLY

3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pressur...

OK

OK

5.

CHECK FUEL PRESSURE SWITCHING VALVE (POWER SOURCE)

(a) Disconnect the fuel pressure switching valve connector.

(b) Connect the Techstream to the DLC3.

(c) Enter the following menus: Powertrain / Engine and ECT

/ Active Test / Activate the Fuel Pressure Switching Valve.

(d) Operate the fuel pressure switching valve.

(e) Measure the voltage according to the value(s) in the

table below.

Standard Voltage:

TESTER

CONNECTION

CONDITION

SPECIFIED

CONDITION

1 (+B) - 2 (E)

High selected in Active

Test

11 to 14 V

NG

GO TO STEP 7

6.

INSPECT FUEL PRESSURE SWITCHING VALVE

(a) Inspect the fuel pressure switching valve

.

NG

REPLACE FUEL PRESSURE SWITCHING VALVE

OK

REPLACE FUEL SUCTION WITH PUMP AND

GAUGE TUBE ASSEMBLY

7.

INSPECT RELAY (F/PMP VSV)

(a) Inspect the F/PMP VSV relay

.

NG

REPLACE RELAY (F/PMP VSV)

3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pressur...

OK

8.

CHECK RELAY (F/PMP VSV POWER SOURCE)

(a) Remove the fuel pressure control valve relay (F/PMP

VSV) 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 VSV relay (5) - Body

ground

Ignition switch

ON

11 to 14 V

NG

GO TO ECM POWER SOURCE CIRCUIT

9.

CHECK HARNESS AND CONNECTOR (FUEL PRESSURE SWITCHING VALVE - F/PMP
RELAY, BODY GROUND)

(a) Disconnect the fuel pressure switching valve connector.

(b) Remove the fuel pressure control valve relay (F/PMP VSV) from the engine room relay block.

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

Standard Resistance:

TESTER CONNECTION

CONDITION

SPECIFIED CONDITION

R9-1 (+B) - F/PMP VSV relay (3)

Always

Below 1 Ω

R9-2 (E) - Body ground

Always

Below 1 Ω

R9-1 (+B) or F/PMP VSV relay (3) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3UR-FBE ENGINE CONTROL SYSTEM: SFI SYSTEM: Fuel Pressur...