Toyota Tundra. Manual — part 1242

Fig. 205: Engine RPM & A/F Sensor Voltage Waveform

HINT:



If the output voltage of the A/F sensor remains at approximately 3.3 V (see ) 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 more,
or 2.8 V or less (see ) 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 10
mph (16 km/h) 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
constant voltage result.

NG : Go to step 10

2008 Toyota Tundra

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

OK : Go to next step.

4. PERFORM CONFIRMATION DRIVING PATTERN

5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

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 the DTCs.

Result

RESULT CHART

B : Go to step 9

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 P2195, P2196, P2197 OR P2198)

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 : REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN

A : Go to next step.

9. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

NO : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT

Display (DTC Output)

Proceed To

P2195, P2196, P2197 or P2198

A

No output

B

Display (DTC Output)

Proceed To

No output

A

P2195, P2196, P2197 or P2198

B

2008 Toyota Tundra

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

PROBLEMS )

YES : DTC CAUSED BY RUNNING OUT OF FUEL

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

PROCEDURE )

NG : REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

OK : Go to next step.

11. INSPECT INTEGRATION RELAY (A/F RELAY) (See INSPECTION PROCEDURE )

NG : REPLACE INTEGRATION RELAY (See ON-VEHICLE INSPECTION )

OK : Go to next step.

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

PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to next step.

13. CHECK AIR INDUCTION SYSTEM

a. Check the air induction system for vacuum leakage.

OK: No leakage from air induction system.

NG : REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK : Go to next step.

14. CHECK FUEL PRESSURE

a. Check the fuel pressure. (See ON-VEHICLE INSPECTION ).

NG : REPAIR OR REPLACE FUEL SYSTEM

OK : Go to next step.

15. INSPECT FUEL INJECTOR

a. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is

poor). (See INSPECTION ).

NG : REPLACE FUEL INJECTOR . (See FUEL INJECTOR ).

2008 Toyota Tundra

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

OK : Go to next step.

16. REPLACE AIR FUEL RATIO SENSOR

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

17. PERFORM CONFIRMATION DRIVING PATTERN

18. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

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 : REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN

A : Go to next step.

19. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

NO : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT
PROBLEMS )

YES : DTC CAUSED BY RUNNING OUT OF FUEL

20. REPLACE AIR FUEL RATIO SENSOR

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

21. PERFORM CONFIRMATION DRIVING PATTERN

22. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

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

Display (DTC Output)

Proceed To

No output

A

P2195, P2196, P2197 or P2198

B

Display (DTC Output)

Proceed To

No output

A

2008 Toyota Tundra

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