Toyota Tundra. Manual — part 1419

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 idling (press the

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

f. 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:



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%.



The sensors react in accordance with increases and decreases in the fuel injection volume.

Standard

FUEL INJECTION - VOLTAGE SPECIFICATION

A/F SENSOR (SENSOR 1) OUTPUT VOLTAGE REFERENCE

Tester Display (Sensor)

Injection Volume

Status

Voltage

AFS B1 S1 (A/F)

+25%

Rich

Less than 3.0

-12.5%

Lean

Higher than 3.35

O2S B1 S2 (HO2)

?25%

Rich

Higher than 0.55

-12.5%

Lean

Less than 0.4

AFS B2 S1 (A/F)

+25%

Rich

Less than 3.0

-12.5%

Lean

Higher than 3.35

O2S B2 S2 (HO2)

+25%

Rich

Higher than 0.55

-12.5%

Lean

Less than 0.4

NOTE:

The A/F sensor has an output delay of a few seconds and the HO2 sensor (for
sensor 2) output 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

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

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.

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 to ON.

c. Turn the Techstream ON.

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

e. Read DTCs.

Result

RESULT REFERENCE

HINT:

If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance)
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 to ON and turn the tester ON.

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

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)

Result

Proceed To

P2195, P2196, P2197 or P2198 is output

A

P2195, P2196, P2197 or P2198 and other DTCs are output

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

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.

Result

RESULT REFERENCE

B : Go to step 12

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 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 B2 S1 and Engine Speed.

f. Check the A/F sensor voltage 3 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

STANDARD VOLTAGE SPECIFICATION

Result

Proceed To

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

A

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

B

Condition

A/F Sensor Voltage

Variation

Reference

(1) and (2)

Remains at approximately

3.3 V

3.1 V to 3.5 V

(3)

Increases to 3.8 V or higher

This occurs during engine deceleration (when fuel-

cut performed)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

HINT:



For more information, see the diagrams below.

Fig. 222: Engine Speed Graph - Normal & Malfunction Condition



If the output voltage of the A/F sensor remains at approximately 3.3 V, see
Malfunction Condition diagram in Fig. 222) under any conditions, including those
above, the A/F sensor may have an open circuit. (This will also happen if the A/F
sensor heater has an open circuit.)



If the output voltage of the A/F sensor remains at either approximately 3.8 V or higher,
or 2.8 V or less, see Malfunction Condition diagram in Fig. 222) under any conditions,
including those above, the A/F sensor may have a short circuit.



The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean
condition and results in a momentary increase in the A/F sensor output voltage.



The ECM must establish a closed throttle valve position learning value to perform fuel
cut. If the battery terminal has been reconnected, the vehicle must be driven over 16
km/h (10 mph) to allow the ECM to learn the closed throttle valve position.



When the vehicle is driven:

The output voltage of the A/F sensor may be below 2.8 V during fuel enrichment. For
the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully
depressed when trying to overtake another vehicle. The A/F sensor is functioning
normally.



The A/F sensor is a current output element; therefore, the current is converted into a
voltage inside the ECM.

Measuring the voltage at the connectors of the A/F sensor or ECM will show a

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra