Toyota Tundra. Manual — part 1570

4. Clear the DTCs (See DTC CHECK/CLEAR ).

HINT:

Even if no DTCs are stored, perform the DTC clear operation to start alcohol concentration learning.

5. Enter the following menus: Powertrain/Engine and ECT/Data List/All/Catalyst Monitor CMPL.

6. Check that Catalyst Monitor CMPL is incomplete.

7. Start the engine.

HINT:

After clearing the DTCs, the engine may become difficult to start if the concentration of alcohol in the
fuel is high. Therefore, it may be necessary to crank the engine a few times before it starts.

8. Warm up the engine until the engine coolant temperature is 75°C (167°F) or more [A].

9. Drive the vehicle at 32 km/h (20 mph) or more and maintain a constant speed for 2 minutes or more [B].

10. After this driving make sure that the Data List "Alcohol Density Learning" is "Compl".

11. Drive the vehicle at between 64 and 113 km/h (40 and 70 mph) and maintain a constant speed for at least

10 minutes [C].

12. Enter the following menus: Powertrain/Engine and ECT/Monitor.

13. Those items will change to Complete as Catalyst Monitor Status.

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

15. Check if any DTCs (any pending DTCs) are output.

HINT:

If Catalyst Monitor Status does not change to Complete, and any pending DTCs fail to set, extend the
driving time.

CONDITIONING FOR SENSOR TESTING

HINT:

Perform the operation with the engine speeds and time durations described below prior to checking the
waveforms of the A/F and HO2 sensors. This is in order to activate the sensors sufficiently to obtain the
appropriate inspection results.

CAUTION: Perform this drive pattern on a level road as much as possible and

strictly observe the posted speed limits and traffic laws while driving.

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Fig. 167: Engine Speed Driving Pattern
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

a. Connect the Techstream to the DLC3.

b. Start the engine and warm it up with all the accessories switched OFF until the engine coolant

temperature stabilizes.

c. Run the engine at an engine speed of between 2500 RPM and 3000 RPM for at least 3 minutes.

d. While running the engine at 3000 RPM and 2000 RPM at 2 second intervals, check the waveforms of the

A/F and HO2 sensors using the Techstream.

HINT:



If either voltage output of the Air-Fuel Ratio (A/F) or Heated Oxygen (HO2) sensor does not
fluctuate, or there is a noise in the waveform of either sensor, the sensor may be malfunctioning.



If the voltage outputs of both the sensors remain lean or rich, the air-fuel ratio may be extremely
lean or rich. In such cases, perform the following Control the Injection Volume for A/F Sensor
using the Techstream.



If the Three-Way Catalytic Converter (TWC) has deteriorated, the HO2 sensor (located behind the
TWC) voltage output fluctuates up and down frequently, even under normal driving conditions
(active air-fuel ratio control is not performed).

Fig. 168: A/F Sensor Output Voltage Waveform
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

HINT:

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.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 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 DTCs.

Result

RESULT REFERENCE

HINT:

If any DTCs other than P0420 or P0430 are output, troubleshoot those DTCs first.

B: GO TO DTC CHART

A: Go to Next Step

2. CHECK SENSOR OUTPUT

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

b. Connect the Techstream to the DLC3.

c. Stop the engine.

d. Turn the ignition switch to ON.

e. Turn the Techstream on.

f. Write down the freeze frame data.

g. Clear the DTCs (See DTC CHECK/CLEAR ).

HINT:

Even if no DTCs are stored, perform the DTC clear operation to start alcohol concentration
learning.

h. Enter the following menus: Powertrain/Engine and ECT/Data List/Flexible Fuel Vehicle.

i. Record data using snapshots.

Result

Proceed to

P0420 or P0430 is output

A

P0420 or P0430 and other DTCs are output

B

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

j. Start the engine.

HINT:

After clearing the DTCs, the engine may become difficult to start if the concentration of alcohol in
the fuel is high. Therefore, it may be necessary to crank the engine a few times before it starts.

k. Drive the vehicle at 32 km/h (20 mph) or more and maintain a constant speed for 2 minutes or

more.

l. After this driving make sure that the Data List "Alcohol Density Learning" is "Compl".

m. Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or

AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

Result

RESULT REFERENCE



Sensor Output Reference Values

SENSOR OUTPUT REFERENCE VALUES

Result

Proceed to

A/F sensor and O2 sensor output both consistently indicate rich or lean
or
Aggregate fuel trim*1 less than -20%
or
Aggregate fuel trim*1 more than 65%

A

A/F sensor output consistently outside range of 3.1 to 3.4 V
and
O2 sensor output and A/F sensor output contradict each other*2

B

A/F sensor output between 3.1 and 3.4 V
and
O2 sensor output consistently indicates rich or lean

C

A/F sensor output between 3.1 and 3.4 V
and
O2 sensor output slowly changes in the range of 0 and 1 V
and
Aggregate fuel trim*1 between -20 and 65%

D

HINT:



*1: Aggregate fuel trim is approximately equal to the following: Short FT + ((1 + Long
FT/100) x (1 + (Alcohol Density Estimate/2/100)) -1) x 100



*2: For example, the A/F sensor output indicates rich while the O2 sensor output indicates
lean.

Air-fuel Ratio A/F Sensor

HO2 Sensor

Lean

Higher than 3.25 V Below 0.4 V

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra