Toyota Tundra. Manual — part 1257

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:



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

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



Injector



Fuel pressure

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-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.

HINT:



DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.



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.



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 P2A00 AND/OR P2A03)

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 P2A00 or P2A03 are output, troubleshoot those DTCs first.

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

A : Go to next step.

4



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

Display (DTC Output)

Proceed To

P2A00 and/or P2A03

A

P2A00 and/or P2A03 and other DTCs

B

2008 Toyota Tundra

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

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

PROCEDURE )

NG : REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

OK : Go to next step.

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

PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to next step.

4. PERFORM CONFIRMATION DRIVING PATTERN

5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

a. Connect the Techstream to the DLC3.

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

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

d. Read DTCs.

Result

RESULT CHART

B : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT
PROBLEMS )

A : Go to next step.

6. REPLACE AIR FUEL RATIO SENSOR

a. Replace the air fuel ratio sensor (See REMOVAL ).

7. PERFORM CONFIRMATION DRIVING PATTERN

8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

a. Connect the Techstream to the DLC3.

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

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

d. Read DTCs.

Result

Display (DTC Output) Proceed To

P2A00 and/or P2A03

A

No output

B

2008 Toyota Tundra

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

RESULT CHART

B : CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC
P0171 PROCEDURE) (See DTC P0171 SYSTEM TOO LEAN (BANK 1); DTC P0172 SYSTEM
TOO RICH (BANK 1); DTC P0174 SYSTEM TOO LEAN (BANK 2); DTC P0175 SYSTEM TOO
RICH (BANK 2) )

A : END

EVAP SYSTEM

RELATED DTCS

DTC MONITORING ITEM REFERENCE

Display (DTC Output) Proceed To

No output

A

P2A00 and/or P2A03

B

DTC

Monitoring Item

P043E

Reference orifice clogged (built into canister pump
module)

P043F

Reference orifice high-flow (built into canister pump
module)

P0441



Purge VSV (Vacuum Switching Valve) stuck
closed



Purge VSV stuck open



Purge flow

P0451



Canister pressure sensor (built into canister
pump module) noise



Canister pressure sensor (built into canister
pump module) signal becomes fixed/flat

P0452

Canister pressure sensor (built into canister pump
module) voltage low

P0453

Canister pressure sensor (built into canister pump
module) voltage high

P0455

EVAP gross leak

P0456

EVAP small leak

P2401

Leak detection pump stuck OFF (built into canister
pump module)

P2402

Leak detection pump stuck ON (built into canister
pump module)

P2419

Vent valve stuck closed (built into canister pump
module)

P2420

Vent valve stuck open (vent) (built into canister
pump module)

2008 Toyota Tundra

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