DTC    P0100    Mass Air Flow Circuit Malfunction

DTC    P0102    Mass Air Flow Circuit Low

DTC    P0103    Mass Air Flow Circuit High

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DESCRIPTION

The Mass Air Flow (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 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 air flow 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 controlled so that the potential of A and B remains equal to maintain the predetermined temperature.

HINT:
When any of these DTCs are set, the ECM enters fail-safe mode. During 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.


A054324E06


DTC No.
DTC Detection Condition
Trouble Area
P0100
Open or short in MAF meter circuit for 3 seconds
  1. Open or short in MAF meter circuit
  1. MAF meter
  1. ECM
P0102
Open in MAF meter circuit for 3 seconds
  1. Open in MAF meter circuit
  1. MAF meter
  1. ECM
P0103
Short in MAF meter circuit for 3 seconds
  1. Short in MAF meter circuit
  1. MAF meter
  1. ECM

MONITOR DESCRIPTION

If there is a defect in the MAF meter or an open short circuit, the voltage level will deviate from the normal operating range. The ECM interprets this deviation as a defect in the MAF meter and sets a DTC.
Example:
When the sensor output voltage is less than 0.2 V or more than 4.9 V, and if either condition continues for more than 3 seconds, the ECM sets a DTC.
This monitor runs for 3 seconds (the first 3 seconds of engine idle) after the engine is started (1 trip detection logic).

HINT:
When DTC P0100, P0102 or P0103 is detected, check the airflow ratio by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / MAF.

Mass Air Flow Rate (gm/s)
Malfunction
Approximately 0.0
  1. Open in MAF meter power source circuit
  1. Open or short in VG circuit
271.0 or more
  1. Open in EVG circuit


WIRING DIAGRAM


A112444E01


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.

1.READ DATA LIST (MASS AIR FLOW RATE)

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine.

  1. Turn the intelligent tester ON.

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

  1. Read the value.

    Result:
    Mass Air Flow Rate (g/s)
    		Proceed to
    Approximately 0.0
    		A
    271.0 or more
    		B
    Between 1.0 and 270.0 *
    		C

    HINT:
    *: The value must change when the throttle valve is opened or closed.



B
Go to step 6

C
CHECK FOR INTERMITTENT PROBLEMS
A


2.INSPECT MASS AIR FLOW METER (POWER SOURCE)
A054396E33

  1. Disconnect the A4 MAF meter connector.

  1. Turn the ignition switch ON.

  1. Measure the voltage of the wire harness side connector.

    Standard voltage:
    Tester Connection
    		Specified Condition
    A4-1 (+B) - Body ground
    		9 to 14 V



NG
Go to step 5
OK


3.INSPECT ECM (VG VOLTAGE)
G035614E24

  1. Start the engine.

  1. Measure the voltage of the ECM connector.

    HINT:
    The shift lever should be on P or N and the A/C switch should be turned OFF.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E15-30 (VG) - E15-29 (E2G)
    		Engine is idling
    		0.5 to 3.0 V



OK
REPLACE ECM
NG


4.CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM)
A112445E01

  1. Disconnect the A4 MAF meter connector.

  1. Disconnect the E15 ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A4-3 (VG) - E15-30 (VG)
    		Below 1 Ω
    A4-2 (E2G) - E15-29 (E2G)
    		Below 1 Ω
    A4-3 (VG) or E15-30 (VG) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE MASS AIR FLOW METER 

5.CHECK WIRE HARNESS (MASS AIR FLOW METER - INTEGRATION RELAY)
A112666E01

  1. Disconnect the A4 MAF meter connector.

  1. Disconnect the 1J integration relay connector from the engine room junction block.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A4-1 (+B) - 1J-5
    		Below 1 Ω
    A4-1 (+B) or 1J-5- Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

CHECK ECM POWER SOURCE CIRCUIT 

6.INSPECT ECM (SENSOR GROUND)
G035614E27

  1. Measure the resistance of the ECM connector.

    Standard resistance:
    Tester Connection
    		Specified Condition
    E15-29 (E2G) - Body ground
    		Below 1 Ω



NG
REPLACE ECM
OK


7.CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM)
A112445E01

  1. Disconnect the A4 MAF meter connector.

  1. Disconnect the E15 ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A4-3 (VG) - E15-30 (VG)
    		Below 1 Ω
    A4-2 (E2G) - E15-29 (E2G)
    		Below 1 Ω
    A4-3 (VG) or E15-30 (VG) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE MASS AIR FLOW METER