Toyota Tundra (2015 year). Manual — part 1177

OR AFS VOLTAGE

B2S1

O2S B2S2

RATIO AND HEATED

OXYGEN SENSOR

CONDITION

Lean/Rich

Lean/Rich

Normal

-

Three-way

catalytic

converter

Gas leaks from

exhaust system

EGR valve

assembly

A

Lean

Lean/Rich

Air fuel ratio sensor

malfunction

-

Air fuel ratio sensor

B

Rich

Lean/Rich

Air fuel ratio sensor

malfunction

-

Air fuel ratio sensor

Lean/Rich

Lean

Heated oxygen sensor

malfunction

-

Heated oxygen

sensor

Gas leaks from

exhaust system

C

Lean/Rich

Rich

Heated oxygen sensor

malfunction

-

Heated oxygen

sensor

Gas leaks from

exhaust system

Lean

Lean

Actual air fuel ratio lean

May

occur

Extremely rich

or lean actual

air fuel ratio

Gas leaks from

exhaust system

EGR valve

assembly

D

Rich

Rich

Actual air fuel ratio rich

-

Extremely rich

or lean actual

air fuel ratio

Gas leaks from

exhaust system

EGR valve

assembly

Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor output voltage

(AFS Voltage) is consistently more than 3.4 V, and the heated oxygen sensor output voltage (O2S) is

consistently less than 0.4 V.

Rich: During the Control the Injection Volume for A/F Sensor Active Test, the AFS Voltage is consistently less

than 3.1 V, and the O2S is consistently more than 0.55 V.

A

OK

ratio sensor and heated oxygen sensor alternate correctly.

B

GO TO STEP 7

C

GO TO STEP 8

D

GO TO STEP 10

3.

CHECK FOR EXHAUST GAS LEAK

(a) Check for exhaust gas leaks.

OK:

No gas leaks.

HINT:

Perform "Inspection After Repair" after repairing or replacing the exhaust system

.

NG

REPAIR OR REPLACE EXHAUST GAS LEAK POINT

4.

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)

(a) Connect the Techstream to the DLC3.

(b) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or

higher.

HINT:

When performing the Active Test, make sure the shift lever is in P or N.
The A/C switch and all accessory switches should be off.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step

Position.

(e) Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the

Data List while performing the Active Test.

HINT:

1UR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0420,P0430; ...

OK

Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.

OK:

MAP and idling condition change in response to EGR step position as follows.

Standard:

-

EGR STEP POSITION (ACTIVE TEST)

0 STEPS

0 TO 30 STEPS

Idling

condition

Steady idling

Idling changes from steady to rough idling or engine stall

MAP

(Data List)

20 to 40 kPa (150 to 300

mmHg)

MAP value is at least +10 kPa (75 mmHg) higher than when EGR

valve is fully closed

OK

GO TO STEP 6

NG

GO TO STEP 5

5.

INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly

.

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly

.

NG

REPLACE EGR VALVE ASSEMBLY

6.

CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)

(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 / Trouble Codes.

(d) Read the DTCs.

Result

1UR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0420,P0430; ...

OK

RESULT

PROCEED TO

P0420

A

P0430

B

P0420 and P0430

A and B

A

REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY

(TWC: FRONT CATALYST AND REAR CATALYST)

B

REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC:

FRONT CATALYST AND REAR CATALYST)

7.

REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor

.

HINT:

Perform "Inspection After Repair" after replacing the air fuel ratio sensor

.

NEXT

GO TO STEP 14

8.

CHECK FOR EXHAUST GAS LEAK

(a) Check for exhaust gas leaks.

OK:

No gas leaks.

HINT:

Perform "Inspection After Repair" after repairing or replacing the exhaust system

.

NG

REPAIR OR REPLACE EXHAUST GAS LEAK POINT

9.

REPLACE HEATED OXYGEN SENSOR

(a) Replace the heated oxygen sensor

.

HINT:

Perform "Inspection After Repair" after replacing the heated oxygen sensor

.

1UR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0420,P0430; ...