Toyota Tundra. Manual — part 1183

OK : Go to next step

3. CHECK AIR INDUCTION SYSTEM

a. Check the air induction system for vacuum leakage.

OK: No leakage from air induction system.

NG : REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK : Go to next step

4. PERFORM ACTIVE TEST USING TECHSTREAM (A/F CONTROL)

a. Connect the Techstream to the DLC3.

b. Start the engine and turn the Techstream ON.

c. Warm up the engine at an engine speed of 2500 RPM for approximately 90 seconds.

d. Enter the following menus: Powertrain/Engine and ECT/Active Test/Control the Injection Volume

for A/F Sensor.

e. Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling

condition (press the RIGHT or LEFT button to change the fuel injection volume).

f. Monitor the voltage outputs of A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and

O2S B2S2) displayed on the Techstream.

HINT:



The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume
by 12.5% or increases the injection volume by 25%.



Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard

VOLTAGE REFERENCE

Result:

RESULT CHART

Tester Display (Sensor)

Injection Volume Status

Voltage

AFS B1 S1 or AFS B2 S1 (A/F)

+25%

Rich

Less than 3.0

AFS B1S1 or AFS B2S1 (A/F)

-12.5%

Lean More than 3.35

O2S B1 S2 or O2S B2 S2 (HO2)

+25%

Rich More than 0.55

O2S B1 S2 or O2S B2 S2 (HO2)

-12.5%

Lean

Less than 0.4

Status AFS

B1S1 or AFS

B2S1

Status O2S

B1S2 or O2S

B2S2

A/F Condition and

A/F Sensor

Condition

Misfire Suspected Trouble Area

Proceed

To

Lean/Rich

Lean/Rich

Normal

-

-

C

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Lean: During Control the Injection Volume for A/F Sensor, the A/F sensor output voltage (AFS) is
consistently more than 3.35 V, and the HO2 sensor output voltage (O2S) is consistently less than
0.4 V. Rich: During Control the Injection Volume for A/F Sensor, the AFS is consistently less than
3.0 V, and the O2S is consistently more than 0.55 V.

Lean/Rich: During Control the Injection Volume for A/F Sensor of the Active Test, the output
voltage of the heated oxygen sensor alternates correctly.

B : Go to step 11

C : Go to step 15

A : Go to next step

5. READ VALUE USING TECHSTREAM (COOLANT TEMP)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON and turn the Techstream ON.

Lean

Lean

Actual air-fuel ratio

lean

May

occur



PCV valve and hose



PCV hose
connections



Injector blockage



Gas leakage from
exhaust system



Air induction system



Fuel pressure



Mass Air Flow
(MAF) meter



Engine Coolant
Temperature (ECT)
sensor

A

Rich

Rich

Actual air-fuel ratio

rich

-



Injector blockage or
blockage



Gas leakage from
exhaust system



Ignition system



Fuel pressure



MAF meter



ECT sensor

Lean

Lean/Rich

A/F sensor

malfunction

-



A/F sensor

B

Rich

Lean/Rich

A/F sensor

malfunction

-



A/F sensor

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

c. Enter the following menus: Powertrain/Engine and ECT/Data List/All Data/Coolant Temp.

d. Read the Data List twice, when the engine is both cold and warmed up.

Standard:

With cold engine: Same as ambient air temperature.

With warm engine: 80 to 100°C (176 to 212°F).

NG : REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK : Go to next step

6. INSPECT MASS AIR FLOW METER

a. Inspect mass air flow meter (See REMOVAL ).

NG : REPLACE MASS AIR FLOW METER (See REMOVAL )

OK : Go to next step

7. CHECK FUEL PRESSURE

a. Check the fuel pressure. (See ON-VEHICLE INSPECTION ).

NG : REPAIR OR REPLACE FUEL SYSTEM

OK : Go to next step

8. CHECK FOR EXHAUST GAS LEAK

OK: No gas leakage.

NG : REPAIR OR REPLACE EXHAUST SYSTEM

OK : Go to next step

9. CHECK SPARK AND IGNITION

HINT:

If the spark plugs or ignition system malfunctions, engine misfire may occur. The misfire count can be
read using the Techstream. Enter the following menus: Powertrain/Engine and ECT/Data List/All
Data/Cylinder #1 Misfire Rate (to Cylinder #6 Misfire Rate).

NG : REPAIR OR REPLACE IGNITION SYSTEM

OK : Go to next step

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

10. INSPECT FUEL INJECTOR ASSEMBLY (INJECTION AND VOLUME)

HINT:

If the injectors malfunction, engine misfire may occur. The misfire count can be read using the
Techstream. Enter the following menus: Powertrain/Engine and ECT/ Data List/All Data/Cylinder #1
Misfire Rate (to Cylinder #6 Misfire Rate).

NG : REPLACE FUEL INJECTOR ASSEMBLY . (See FUEL INJECTOR ).

OK : Go to next step

11. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) . (See INSPECTION

PROCEDURE).

NG : REPLACE AIR FUEL RATIO SENSOR . (See REMOVAL).

OK : Go to next step

12. INSPECT INTEGRATION RELAY (A/F RELAY) . (See INSPECTION PROCEDURE).

NG : REPLACE INTEGRATION RELAY . (See ON-VEHICLE INSPECTION).

OK : Go to next step

13. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) (See INSPECTION

PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to next step

14. REPLACE AIR FUEL RATIO SENSOR

a. Replace the A/F sensor (See REMOVAL ).

15. PERFORM CONFIRMATION DRIVING PATTERN

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra