Toyota Tundra. Manual — part 1437



For Bank 2 refers to the bank that includes No. 2 cylinder.



DTC P2A00 or P2A03 may be 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 to ON.

c. Turn the Techstream ON.

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

e. Read DTCs.

Result

RESULT REFERENCE

HINT:

If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance)
are output, troubleshoot those DTCs first.

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

A : Go to Next Step

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 (ECM - AIR-FUEL RATIO SENSOR) (See

INSPECTION PROCEDURE )

Result

Proceed To

P2A00 and/or P2A03 are output

A

P2A00 and/or P2A03 and other DTCs are output

B

2008 Toyota Tundra

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

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 to ON and turn the Techstream ON.

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

d. Read pending DTCs.

Result

RESULT REFERENCE

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 to ON and turn the Techstream ON.

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

d. Read pending DTCs.

Result

RESULT REFERENCE

B : REPLACE ECM (See REMOVAL )

A : END

Result

Proceed To

P2A00 and/or P2A03 is output

A

No DTC is output

B

Result

Proceed To

No DTC is output

A

P2A00 and/or P2A03 are output

B

2008 Toyota Tundra

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

DTC U0101 LOST COMMUNICATION WITH TCM

DESCRIPTION

The Transmission Control Module (TCM) and ECM perform 2-way communications with each other via the
Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine RPM,
required engine torques, warning indicators in the combination meter, DTCs and other data. The ECM sends
signals to the TCM concerning engine RPM, opening angles of the throttle valve, temperature of intake air,
temperature of engine coolant, engine torques and other data. If the TCM cannot communicate with the ECM,
the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.

DTC DETECTION CONDITION AND TROUBLE AREA

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

INSPECTION PROCEDURE

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101)

DTC Code

DTC Detection Condition

Trouble Area

U0101

No communication from TCM continues



Open or short in TCM and ECM circuit



TCM



ECM

Related DTCs

U0101: Verify communication

Required Sensors/Components (Main)

ECM

Required Sensors/Components (Sub)

-

Frequency of Operation

Continuous

Duration

1.25 seconds

MIL Operation

Immediate

Sequence of Operation

None

Monitor runs whenever following DTCs are not present

None

Battery voltage

10.5 V or higher

Ignition switch

ON

Starter

OFF

Communication signal

Lost communication with TCM

2008 Toyota Tundra

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

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON.

c. Turn the Techstream ON.

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

e. Read the DTCs.

Result

RESULT REFERENCE

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

A : Go to Next Step

2. REPLACE ECM

a. Replace the ECM. (See REMOVAL ).

3. CHECK IF DTC RECURS

a. Connect the Techstream to the DLC3.

b. Clear the DTC. (See DTC CHECK/CLEAR ).

c. Start the engine.

d. Read the DTCs.

Result

RESULT REFERENCE

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

A : END

EVAP SYSTEM

RELATED DTCS

DTC CHART

Result

Proceed To

U0101 is output

A

U0101 and other DTCs are output

B

Result

Proceed To

No DTC is output

A

Other DTCs are output

B

DTC

Monitoring Item

P043E

Reference orifice clogged (built into canister pump

2008 Toyota Tundra

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