Toyota Tundra. Manual — part 1241

h. Change the transmission to 2nd gear.

i. Drive the vehicle at the proper vehicle speed to perform fuel-cut operation (refer to the following HINT).

HINT:

Fuel-cut is performed when the following conditions are met:



Accelerator pedal fully released.



Engine speed is 2500 RPM or more (fuel injection returns at 1000 RPM).

j. Accelerate the vehicle to 40 mph (64 km/h) or more by depressing the accelerator pedal for at least 10

seconds.

k. Soon after performing step (j) above, release the accelerator pedal for at least 4 seconds without

depressing the brake pedal, in order to execute fuel-cut control.

l. Allow the vehicle to decelerate until the vehicle speed declines to less than 6 mph (10 km/h).

m. Repeat steps from (g) through (j) above at least 3 times in one driving cycle.

HINT:

Completion of all O2S (A/F) Monitor is required to change the value in Data List.

INSPECTION PROCEDURE

HINT:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function
provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine
whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are
malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation
using the Techstream.

1. Connect the Techstream to the DLC3.

2. Start the engine and turn the Techstream ON.

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

4. On the Techstream, enter the following menus: Powertrain/Engine and ECT/Active Test/Control the

Injection Volume for A/F sensor.

5. Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT

button to change the fuel injection volume.)

6. Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and

O2S B2 S2) displayed on the Techstream.

HINT:

2008 Toyota Tundra

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



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.

VOLTAGE REFERENCE

VOLTAGE REFERENCE



Following the Control the Injection Volume for A/F sensor procedure enables technicians to check
and graph the voltage outputs of both the A/F and HO2 sensors.



To display the graph, enter the following menus: Powertrain/Engine and ECT/Active Test/Control
the Injection Volume for A/F Sensor/A/F Control System/AFS B1 S1 and O2S B1 S2 or AFS B2
S1 and O2S B2 S2.

HINT:

Tester Display (Sensor)

Injection Volume Status

Voltage

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

+25%

Rich

Less than 3.0 V

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

-12.5%

Lean More than 3.35 V

O2S B1 S2 or O2S B2 S2 (HO2)

+25%

Rich More than 0.55 V

O2S B1 S2 or O2S B2 S2 (HO2)

-12.5%

Lean

Less than 0.4 V

NOTE:

The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and
the Heated Oxygen (HO2) sensor has a maximum output delay of
approximately 20 seconds.

Case

A/F Sensor (Sensor 1) Output

Voltage

HO2 Sensor (Sensor 2)

Output Voltage

Main Suspected Trouble Area

1

-

2



A/F sensor



A/F sensor heater



A/F sensor circuit

3



HO2 sensor



HO2 sensor heater



HO2 sensor circuit

4



Injector



Fuel pressure



Gas leakage from exhaust
system (Air-fuel ratio
extremely rich or lean)

2008 Toyota Tundra

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



Read freeze frame data using the Techstream. Freeze frame data records the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was
moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other
data from the time the malfunction occurred.



A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would
cause the engine to run rich.



A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would
cause the engine to run lean.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195, P2196, P2197 OR P2198)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON.

c. Turn the Techstream ON.

d. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

e. Read DTCs.

Result

RESULT CHART

HINT:

If any DTCs other than P2195, P2196, P2197 or P2198 are output, troubleshoot those DTCs first.

B : GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A : Go to next step.

2. READ VALUE USING TECHSTREAM (TEST VALUE OF A/F SENSOR)

a. Connect the Techstream to the DLC3.

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

c. Clear DTCs (See DTC CHECK/CLEAR ).

d. Allow the vehicle to drive in accordance with the drive pattern described in the CONFIRMATION

DRIVING PATTERN.

e. Enter the following menus: Powertrain/Engine and ECT/Monitor/O2 Sensor.

f. Check that the status of O2 Sensor is Complete. If the status is still Incomplete, drive the vehicle

according to the driving pattern again.

g. Enter the following menus: Powertrain/Engine and ECT/Monitor/O2 Sensor/Details/RANGE B1

S1.

h. Check the test value of the A/F sensor output current during fuel-cut.

Display (DTC Output)

Proceed To

P2195, P2196, P2197 or P2198

A

P2195, P2196, P2197 or P2198 and other DTCs

B

2008 Toyota Tundra

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

Result

RESULT CHART

B : Go to step 20

A : Go to next step.

3. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF A/F SENSOR)

a. Connect the Techstream to the DLC3.

b. Start the engine.

c. Turn the Techstream ON.

d. Warm up the Air-Fuel Ratio (A/F) sensor at an engine speed of 2500 RPM for 90 seconds.

e. Enter the following menus: Powertrain/Engine and ECT/Data List/A/F Control

System/Snapshot/AFS B1 S1 or AFS B1 S1 and Engine Speed.

f. Check the A/F sensor voltage three times, when the engine is in each of the following conditions:

1. While idling (check for at least 30 seconds)

2. At an engine speed of approximately 2500 RPM (without any sudden changes in engine

speed)

3. Raise the engine speed to 4000 RPM and then quickly release the accelerator pedal so that

the throttle valve is fully closed.

Standard

VOLTAGE REFERENCE

HINT:

For more information, see the diagrams below.

Test Value

Proceed To

Within normal range (1.4 mA or more, and less than 3.6 mA)

A

Outside normal range (Less than 1.4 mA, or 3.6 mA or more)

B

Condition

A/F Sensor Voltage

Variation

Reference

(1) and (2)

Changes at approximately
3.3 V

Between 3.1 V and 3.5 V

(3)

Increases to 3.8 V or more

This occurs during engine deceleration (when fuel-
cut performed)

2008 Toyota Tundra

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