DTC    P0101    Mass Air Flow Circuit Range / Performance Problem

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DESCRIPTION

The Mass Air Flow (MAF) meter is a sensor that measures the amount of air flowing through the valve.
The ECM (Included in HV Control ECU) uses this information to determine the fuel injection time and to prove 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 given 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 in 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 circuit is constructed so that the platinum hot wire and the temperature sensor provide a bridge circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the predetermined temperature.

HINT:
When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine RPM and throttle valve position. Fail-safe mode continues until a pass condition is detected.


A094565E03


DTC No.
DTC Detection Condition
Trouble Area
P0101
  1. High voltage:
    Conditions (a), (b) and (c) continue for more than 5 seconds (2 trip detection logic):
    1. Engine speed less than 2,000 rpm
    2. Engine coolant temperature 70°C (158°F) or higher
    3. Output voltage of Mass Air Flow (MAF) meter more than 2.2 V (varies with Throttle Position sensor voltage)
  1. Low voltage:
    Conditions (a) and (b) continue for more than 5 seconds (2 trip detection logic):
    1. Engine speed more than 300 rpm
    2. Output voltage of MAF meter less than 0.7 V (varies with throttle position sensor voltage)
MAF meter

WIRING DIAGRAM

Refer to DTC P0100 (Click here).

INSPECTION PROCEDURE

HINT:
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON.

  1. Turn the tester ON.

  1. Enter the following menus: Powertrain / Engine / DTC.

  1. Read DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    P0101 and other DTCs
    		A
    P0101
    		B

    HINT:
    If any DTCs other than P0101 are output, troubleshoot those DTCs first.



B
REPLACE MASS AIR FLOW METER
A

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