Dtc P0102 Mass Air Flow Circuit Low


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING GTS (MAF)

INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)

INSPECT MASS AIR FLOW METER

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - NO. 1 INTEGRATION RELAY)

CHECK HARNESS AND CONNECTOR (SENSOR GROUND)

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

DTC P0102 Mass Air Flow Circuit Low

DTC P0103 Mass Air Flow Circuit High


DESCRIPTION

The mass air flow 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 the appropriate air fuel ratio.
Inside the mass air flow 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 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 circuit is constructed so that the platinum hot wire and the temperature sensor create 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 stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine speed and throttle valve position. The ECM continues operating fail-safe mode until a pass condition is detected.

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0102 Mass Air Flow Circuit Low


DTC No.
DTC Detection Condition
Trouble Area
P0102
The mass air flow meter voltage is below 0.2 V for 3 seconds (1 trip detection logic).
  1. Open or short in mass air flow meter circuit
  2. Mass air flow meter
  3. ECM
P0103
The mass air flow meter voltage is higher than 4.9 V for 3 seconds (1 trip detection logic).
  1. Open or short in mass air flow meter circuit
  2. Mass air flow meter
  3. ECM

HINT:
When any of these DTCs are output, check the airflow rate by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

Mass Airflow Rate (gm/sec.)
Malfunction
Approximately 0.0
  1. Open in mass air flow meter power source circuit
  2. Open or short in VG circuit
160.0 or more
Open in E2G circuit

MONITOR DESCRIPTION

If there is a defect in the mass air flow meter or an open or short circuit, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the mass air flow meter and stores a DTC.
Example:
When the sensor output voltage remains below 0.2 V, or higher than 4.9 V, for more than 3 seconds, the ECM stores a DTC.
If the malfunction is not repaired successfully, a DTC is stored 3 seconds after the engine is next started.

WIRING DIAGRAM

  1. for Automatic Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0102 Mass Air Flow Circuit Low

  1. for Manual Transmission

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0102 Mass Air Flow Circuit Low


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
Read freeze frame data using the GTS. 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.READ VALUE USING GTS (MAF)

  1. Connect the GTS to the DLC3.

  1. Start the engine.

  1. Turn the GTS on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

  1. Read the values displayed on the GTS.

    Result
    Mass Airflow Rate (gm/sec.)
    		Proceed to
    0.0
    		A
    160.0 or more
    		B
    Between 1.0 and 160.0*
    		C
    HINT:
    *: The value must change when the throttle valve is open or closed with the engine running.


B
Go to step 6

C
CHECK FOR INTERMITTENT PROBLEMS (LandCruiser RM000000PDQ18TX.html)
A


2.INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0102 Mass Air Flow Circuit Low

  1. Disconnect the mass air flow meter connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    C33-3 (+B) - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Mass Air Flow Meter)

  1. Reconnect the mass air flow meter connector.



NG
Go to step 5
OK


3.INSPECT MASS AIR FLOW METER

  1. Inspect the mass air flow meter (LandCruiser RM000002PPR02RX.html).

    HINT:
    for Automatic Transmission
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03SX.html).


NG
REPLACE MASS AIR FLOW METER (LandCruiser RM000000VW603AX.html)
OK


4.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

  1. Disconnect the mass air flow meter connector.

  1. Disconnect the ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance (Check for Open):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-5 (VG) - C34-14 (VG)
    		Always
    		Below 1 Ω
    C33-4 (E2G) - C35-18 (E2G)
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-5 (VG) - C35-14 (VG)
    		Always
    		Below 1 Ω
    C33-4 (E2G) - C35-13 (E2G)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-5 (VG) or C34-14 (VG) - Body ground
    		Always
    		10 kΩ or higher
    C33-4 (E2G) or C35-18 (E2G) - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-5 (VG) or C35-14 (VG) - Body ground
    		Always
    		10 kΩ or higher
    C33-4 (E2G) or C35-13 (E2G) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM00000329203TX.html)

5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - NO. 1 INTEGRATION RELAY)

  1. Disconnect the mass air flow meter connector.

  1. Remove the No. 1 integration relay from the engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    C33-3 (+B) - 1B-4
    		Always
    		Below 1 Ω
    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C33-3 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the mass air flow meter connector.

  1. Reinstall the No. 1 integration relay.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CHECK ECM POWER SOURCE CIRCUIT (LandCruiser RM000001DN80BOX.html)

6.CHECK HARNESS AND CONNECTOR (SENSOR GROUND)

  1. Disconnect the mass air flow meter connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (E2G) - Body ground
    		Always
    		Below 1 Ω

  1. Reconnect the mass air flow meter connector.

    HINT:
    Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (LandCruiser RM000004NJC03SX.html).


NG
Go to step 7
OK

REPLACE MASS AIR FLOW METER (LandCruiser RM000000VW603AX.html)

7.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

  1. Disconnect the mass air flow meter connector.

  1. Disconnect the ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance (Check for Open):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (E2G) - C35-18 (E2G)
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (E2G) - C35-13 (E2G)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (E2G) or C35-18 (E2G) - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C33-4 (E2G) or C35-13 (E2G) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the mass air flow meter connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM00000329203TX.html)