Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000000UBW00JX
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0101; Mass Air Flow Circuit Range / Performance Problem; 2007 MY LX470 [08/2006 -        ]

DTC

P0101

Mass Air Flow Circuit Range / Performance Problem

DESCRIPTION

Refer to DTC P0100 2007 MY LX470 [08/2006 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0100,P0102,P0103; Mass Air Flow Circuit Malfunction+ .

DTC No.

DTC Detection Condition

Trouble Area

P0101

Conditions (a), (b), (c), (d) and (e) are met (2 trip detection logic):

(a) Engine running

(b) Engine coolant temperature 70°C (158°F) or higher

(c) Throttle Position (TP) sensor voltage 0.24 V or more

(d) Average engine load value ratio less than 0.4, or more than 2.2 (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

(e) Average air-fuel ratio less than -20%, or more than 20%
  • Mass Air Flow (MAF) meter
  • Air induction system
  • PCV hose connections

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 these components of the MAF meter. 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

Related DTCs

P0101: MAF Meter Rationality (low voltage)

P0101: MAF Meter Rationality (high voltage)

Required Sensors/Components (Main)

MAF meter

Required Sensors/Components (Related)

Crankshaft position sensor, ECT sensor, Throttle position sensor

Frequency of Operation

Continuous

Duration

10 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

ALL:

Monitor will run whenever these DTCs are not present

P0115 - P0118 (ECT sensor)

P0120 - P0223, P2135 (TP sensor)

P0125 (insufficient ECT for closed loop)

P0335 (CKP sensor)

Throttle position

0.24 V or more

Engine

Running

Battery voltage

10.5 V or more

ECT

70°C (158°F) or more

IAT sensor circuit fail

Not detected

ECT sensor circuit fail

Not detected

CKP sensor circuit fail

Not detected

TP sensor circuit fail

Not detected

Canister pressure sensor circuit fail

Not detected

Leak detection pump fail

Not detected

Vent valve fail

Not detected

TYPICAL MALFUNCTION THRESHOLDS

Average engine load

Less than 0.85% or 1.28% or more

COMPONENT OPERATING RANGE

Mass air flow meter voltage

Between 0.4 and 2.2 V

Average air-fuel ratio

Less than -20% or more than 20%

WIRING DIAGRAM

Refer to DTC P0100 2007 MY LX470 [08/2006 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0100,P0102,P0103; Mass Air Flow Circuit Malfunction+ .

CONFIRMATION DRIVING PATTERN

HINT:

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

  1. Connect the intelligent tester to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the tester ON.
  4. Clear DTCs 2007 MY LX470 [08/2006 -        ]; 2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: DTC CHECK / CLEAR .
  5. Start the engine, and warm it up until the engine coolant temperature reaches 70°C (158°F) or higher.
  6. Drive the vehicle at approximately 62 mph (100 km/h) for 20 seconds or more.
  7. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES and check if any DTCs (any pending DTCs) are set.

INSPECTION PROCEDURE

HINT:

Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.

PROCEDURE

1.

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0101)

(a) Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

(b) Turn the ignition switch ON.

(c) Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

(d) Read the DTCs.

Display (DTC output)

Proceed to

P0101 and other codes are output

A

Only P0101 is output

B

HINT:

If any other codes besides P0101 are output, perform troubleshooting for those DTCs first.

B

GO TO RELEVANT DTC CHART

A

2.

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

3.

CHECK VENTILATION HOSE

OK:

Ventilation hose is connected correctly and is not damaged.

NG

REPAIR OR REPLACE VENTILATION HOSE

OK

REPLACE MASS AIR FLOW METER