Toyota Tundra. Manual — part 1436

Fig. 243: Confirmation Driving Pattern Graph

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON.

c. Turn the Techstream ON.

d. Clear DTCs (if set). (See DTC CHECK/CLEAR ).

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

f. Check that RES RATE B1S1 is Incomplete.

g. Start the engine and warm it up.

h. Drive the vehicle at a constant speed of between 40 and 120 km/h (25 and 75 mph) for 3 minutes.

i. Check the monitor result values on the or Techstream by entering the following menus:

Powertrain/Engine and ECT/Monitor/O2 Sensor/Details/RES RATE B1S1 or RES RATE B2S1/Details.

j. If the values indicated on the Techstream do not change, perform READINESS MONITOR DRIVE

PATTERN for the A/F sensor and the heated oxygen sensor, see READINESS MONITOR DRIVE
PATTERN.

HINT:

Completion of all A/F sensor monitors is required to change the value in RES RATE B1S1 or RES RATE
B2S1.

k. Note the value of the Monitor Result.

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

m. Check if any DTCs (any pending DTCs) are set.

MONITOR STRATEGY

MONITOR STRATEGY

2008 Toyota Tundra

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

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

Related DTCs

P2A00: Air-Fuel Ratio (A/F) sensor slow response (bank 1)
P2A03: Air-Fuel Ratio (A/F) sensor slow response (bank 2)

Required Sensors/Components (Main)

A/F sensor

Required Sensors/Components (Related)

Vehicle speed sensor, Crankshaft position sensor

Frequency of Operation

Once per driving cycle

Duration

10 to 15 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not present

P0031, P0032, P0051, P0052 (A/F Sensor Heater -
Sensor 1)
P0102 - P0103 (MAF meter)
P0110 - P0113 (IAT sensor)
P0115 - P0118 (ECT sensor)
P0120 - P0223, P2135 (TP sensor)
P0125 (Insufficient ECT for Closed Loop)
P0171, P0172 (Fuel system)
P0300 - P0308 (Misfire)
P0335 (CKP sensor)
P0455, P0456 (EVAP system)
P0500 (VSS)
P2196, P2198 (A/F sensor - rationality)
P2237, P2240 (A/F sensor - open)
P2440 (AIR control valve stuck open)
P2441 (AIR control valve stuck close)
P2444 (AIP stuck On)
P2445 (AIP stuck Off)

Active A/F control

Performing

Active A/F control performed when following
conditions met

-

Engine coolant temperature

75°C (167°F) or more

Battery voltage

11 V or higher

Idle

OFF

Engine RPM

Less than 4000 RPM

A/F sensor status

Activated

Fuel-cut

OFF

Engine load

10 to 70%

Shift position

2 or more

Catalyst monitor

Not yet

Intake air amount

2.5 to 14 g/sec.

2008 Toyota Tundra

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

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

WIRING DIAGRAM

Refer to DTC P2195 .

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.

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 Active Test operation with the engine in an idling condition (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%.



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

Standard

FUEL INJECTION - VOLTAGE SPECIFICATION

Response rate deterioration level

Less than 0.12 V

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

2008 Toyota Tundra

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

A/F SENSOR (SENSOR 1) OUTPUT 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:



Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located
near the engine assembly.



DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.



DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.



For Bank 1 refers to the bank that includes No. 1 cylinder.

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 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 (2UZ-FE) - Tundra