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P0102 P0103

DTC    P0102    Mass or Volume Air Flow Circuit Low Input

DTC    P0103    Mass or Volume Air Flow Circuit High Input


 

DESCRIPTION

The mass air flow meter sub-assembly 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 sub-assembly, 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 flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant temperature value of the hot wire, current is applied to these components in the mass air flow meter sub-assembly. 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 either 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 speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.

 


P0102 P0103 / Lexus CT200h / ZWA10


 

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

HINT:

When any of these DTCs are set, check the air-flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / MAF.

 

Mass Air Flow Rate (gm/sec) Malfunction
Approximately 0.0
  1. Open in mass air flow meter sub-assembly power source circuit
  2. Open or short in VG circuit
271.0 or more Open in E2G circuit


MONITOR DESCRIPTION

If there is a defect in the mass air flow meter sub-assembly 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 sub-assembly circuit and sets a DTC.
Example:
When the sensor output voltage remains less than 0.2 V, or higher than 4.9 V, for more than 3 seconds, the ECM sets a DTC.
 

MONITOR STRATEGY

 

Frequency of Operation Continuous

 

CONFIRMATION DRIVING PATTERN

  1. Put the engine in inspection mode (maintenance mode).
  2. Start the engine and wait for 5 seconds or more.

 

WIRING DIAGRAM


P0102 P0103 / Lexus CT200h / ZWA10


 

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 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
1.READ DTC OUTPUT (DTC P0102 AND P0103)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  1. Read the DTCs.
     

    Result 
    Result Proceed to
    DTC P0102 is output A
    DTC P0103 is output B

     

 

  B
Go to step 5
 
A  
 

 

2.INSPECT MASS AIR FLOW METER SUB-ASSEMBLY (POWER SOURCE VOLTAGE)


 

P0102 P0103 / Lexus CT200h / ZWA10
  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Turn the power switch on (IG).

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

     

    Standard Voltage:
    Tester Connection Switch Condition Specified Condition
    D5-3 (+B) - Body ground Power switch on (IG) 11 to 14 V

     

    Text in Illustration 
    *a Front view of wire harness connector
    (to Mass Air Flow Meter Sub-assembly)

     

 

  NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - MASS AIR FLOW METER SUB-ASSEMBLY)
 
OK  
 

 

3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Disconnect the ECM connector.

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

     

    Standard Resistance:
     
    Tester Connection Condition Specified Condition
    D5-5 (VG) - D27-94 (VG) Always Below 1 Ω
    D5-4 (E2G) - D27-117 (E2G) Always Below 1 Ω
    D5-5 (VG) or D27-94 (VG) - Body ground Always 10 kΩ or higher

     

     

 

  NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
 

 

4.INSPECT MASS AIR FLOW METER SUB-ASSEMBLY
  1. Perform On-vehicle inspection.

  1. Perform Inspection.

  1. Inspect the function of the mass air flow meter sub-assembly.

    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Put the engine in inspection mode (maintenance mode).

    5. Start the engine.

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

    7. Check that the reading of MAF changes when the engine is raced.

      OK:

      The reading changes.

       

       

     

 

  NG
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY 
 
OK  
 
REPLACE ECM 

 

5.CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
  1. Disconnect the mass air flow meter sub-assembly connector.

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

    Standard Resistance:

     
    Tester Connection Condition Specified Condition
    D5-4 (E2G) - Body ground Always Below 1 Ω

     

     

 

  NG
Go to step 6
 
OK  
 
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY 

 

6.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
  1. Disconnect the mass air flow meter sub-assembly connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

     
    Tester Connection Condition Specified Condition
    D5-4 (E2G) - D27-117 (E2G) Always Below 1 Ω
  NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
 
REPLACE ECM