Toyota Tundra. Manual — part 1383

Fig. 151: Voltage Output Graph

INSPECTION PROCEDURE

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 (See DIAGNOSTIC TROUBLE CODE CHART )

Result

Proceed To

P0420 or P0430 is output

A

P0420 or P0430 and other DTCs are output

B

2008 Toyota Tundra

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

A : Go To Next Step

2. PERFORM ACTIVE TEST USING TECHSTREAM (A/F CONTROL)

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 in an idling

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

f. Monitor the voltage outputs 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.

Result:

A/F sensor reacts in accordance with increases and decreases in fuel injection volume:

+25% = Rich output:

Less than 3.0 V

-12.5% = Lean output:

More than 3.35 V

A/F SENSOR (SENSOR 1) OUTPUT VOLTAGE SPECIFICATION

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



Injector

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.

Result

RESULT REFERENCE

B : REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

C : Go to step 4

D : CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR-FUEL RATIO,
REPLACE FAULTY AREA AND GO TO NEXT STEP

A : Go To Next Step

3. INSPECT FOR EXHAUST GAS LEAK

OK: No gas leakage.

Result

RESULT REFERENCE

B : Go to step 5

A : REPAIR OR REPLACE EXHAUST GAS LEAK POINT

4



Fuel pressure



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

Result Proceed To
Case 1

A

Case 2

B

Case 3

C

Case 4

D

Result Proceed To
NG

A

OK

B

2008 Toyota Tundra

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

4. INSPECT FOR EXHAUST GAS LEAK

OK: No gas leakage.

NG : REPAIR OR REPLACE EXHAUST GAS LEAK POINT

OK : REPLACE HEATED OXYGEN SENSOR (See REMOVAL )

5. CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)

a. According to the output DTCs in the step 1 (Check Any Other DTCs Output), proceed to next step

referring to the table below.

Result

RESULT REFERENCE

B : REPLACE FRONT EXHAUST PIPE ASSEMBLY . (See EXHAUST PIPE (EXCEPT
REGULAR CAB STANDARD DECK) ).

C : REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (FRONT NO. 2 AND NO. 3
EXHAUST PIPE SUB-ASSEMBLY) . (See EXHAUST PIPE (FOR REGULAR CAB STANDARD
DECK) ).

D : REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY . (SeeEXHAUST PIPE (EXCEPT
REGULAR CAB STANDARD DECK) ).

A : REPLACE FRONT EXHAUST PIPE ASSEMBLY . (See EXHAUST PIPE (FOR REGULAR
CAB STANDARD DECK) ).

DTC P043E EVAPORATIVE EMISSION SYSTEM LEAK DETECTION REFERENCE ORIFICE
LOW FLOW; DTC P043F EVAPORATIVE EMISSION SYSTEM REFERENCE ORIFICE HIGH
FLOW; DTC P2401 EVAPORATIVE EMISSION LEAK DETECTION PUMP STUCK OFF; DTC
P2402 EVAPORATIVE EMISSION LEAK DETECTION PUMP STUCK ON; DTC P2419
EVAPORATIVE EMISSION SYSTEM SWITCHING VALVE CONTROL CIRCUIT LOW

DTC SUMMARY

DTC SUMMARY

Result

Proceed To

P0430 (for Regular Cab Standard Deck)

A

P0430 (except Regular Cab Standard Deck)

B

P0420 (for Regular Cab Standard Deck)

C

P0420 (except Regular Cab Standard Deck)

D

P0420 and P0430 (for Regular Cab Standard Deck)

A and C

P0420 and P0430 (except Regular Cab Standard Deck)

Band D

2008 Toyota Tundra

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