Toyota Tundra. Manual — part 1522

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

h. Read DTCs.

Result

RESULT REFERENCE

B: REPLACE ECM (See REMOVAL )

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

DTC P0101 MASS AIR FLOW CIRCUIT RANGE/PERFORMANCE PROBLEM

DESCRIPTION

Refer to DTC P0102 .

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE CHART

Result

Proceed to

No DTC is output

A

P0037, P0038, P0057, P0058, P0141 and/or P0161 are output

B

DTC

DTC Detection Condition

Trouble Area

P0101

Conditions (a), (b), (c), (d) and (e)
continue for more than 10 seconds
(2 trip detection logic):

a. Engine running

b. Engine coolant temperature

70°C (158°F) or higher

c. Throttle Position (TP) sensor

voltage 0.2 V or more and
3.6 V or less

d. Average engine load value

ratio less than 0.85, or more
than 1.29 (varies with
estimated engine load)

Average engine load value
ratio = Average engine load
based on MAF meter
output/Average engine load
estimated from driving
conditions



Mass Air Flow (MAF) meter



Air induction system



PCV hose connections

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

MONITOR DESCRIPTION

The MAF meter is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses
this information to determine the fuel injection time and to provide an appropriate air-fuel ratio. Inside the MAF
meter, there is a heated platinum wire which is exposed to the flow of intake air. By applying a specific
electrical current to the wire, the ECM heats it to a specific temperature. The flow of incoming air cools both
the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM
varies the voltage applied to the wire and internal thermistor. The voltage level is proportional to the airflow
through the sensor, and the ECM uses it to calculate the intake air volume. The ECM monitors the average
engine load value ratio to check the MAF meter for malfunctions. The average engine load value ratio is
obtained by comparing the average engine load calculated from the MAF meter output to the average engine
load estimated from the driving conditions, such as the engine speed and the throttle opening angle. If the
average engine load value ratio is below the threshold value, the ECM determines that the intake air volume is
low, and if the average engine load value ratio is above the threshold value, the ECM determines that the intake
air volume is high.

If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is set.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

e. Average air-fuel ratio less

than -15%, or more than 15%

Related DTCs

P0101: Mass air flow meter rationality

Required Sensors/Components
(Main)

Mass air flow meter

Required Sensors/Components
(Related)

Crankshaft Position (CKP) sensor, Engine Coolant Temperature (ECT)
sensor and Throttle Position (TP) sensor

Frequency of Operation

Continuous

Duration

10 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs
not present

P0112, P0113 (Intake Air Temperature Sensor)
P0115, P0117, P0118 (Engine Coolant Temperature Sensor)
P0335 (Crankshaft Position Sensor)
P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135
(Throttle Position Sensor)
P0452, P0453 (EVAP System)
P2401, P2402 (Leak Detection Pump)
P2419, P2420 (Vent Valve)

Throttle position (TP sensor voltage)

0.2 V or more and 3.6 V or less

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

Refer to DTC P0102 .

CONFIRMATION DRIVING PATTERN

HINT:

Performing this confirmation pattern will activate the mass air flow performance monitor.

Fig. 63: Vehicle Speed Driving Pattern
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Time after engine start

5 seconds or more

Battery voltage

10.5 V or more

Engine coolant temperature

70°C (158°F) or more

Estimated load

30 to 100%

Both of following conditions 1 and 2
met

-

1. Averaged engine load value ratio

Less than 0.85, or more than 1.29 (varies with estimated engine
load)

2. Averaged air-fuel ratio

Less than -15%, or more than 15%

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the Techstream on.

4. Clear DTCs (See DTC CHECK/CLEAR ).

HINT:

Even if no DTCs are stored, perform the DTC clear operation to start alcohol concentration learning.

5. Start the engine.

HINT:

After clearing the DTCs, the engine may become difficult to start if the concentration of alcohol in the
fuel is high. Therefore, it may be necessary to crank the engine a few times before it starts.

6. Warm it up until the ECT reaches 75°C (167°F) or higher [A].

7. Drive the vehicle at 32 km/h (20 mph) or more and maintain a constant speed for 2 minutes or more [B].

HINT:

Make sure that the Data List "Alcohol Density Learning" is "Compl".

8. Drive the vehicle at approximately 100 km/h (62 mph) for 20 seconds or more [C].

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

10. Check if any DTCs (any pending DTCs) are output.

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 P0101)

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

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra