P0103

2ZR-FE ENGINE CONTROL: SFI SYSTEM: P0102,P0103: Mass or Volume Air Flow Circuit Low Input


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 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. 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 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.









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.





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 circuit and sets a DTC.

Example:

When the sensor output voltage remains less than 0.2 V, or more than 4.9 V, for more than 3 seconds, the ECM sets a DTC.

If the malfunction is not repaired successfully, a DTC is set 3 seconds after the engine is next started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0102:

P0102:

P0103:

P0103:

COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
Read freeze frame data using the Techstream. 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.

PROCEDURE

1. READ DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the Ignition switch to ON.

(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(d) Read the DTCs.

Result:





HINT
*: The value should change when the throttle valve is opened or closed with the engine running.

B -- CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
A -- Continue to next step.

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





(a) Disconnect the mass air flow meter connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:





(d) Reconnect the mass air flow meter connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - MASS AIR FLOW METER)
OK -- Continue to next step.

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





(a) Disconnect the mass air flow meter meter connector.

(b) Disconnect the ECM connector.

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

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the mass air flow meter meter connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
OK -- Continue to next step.

4. INSPECT MASS AIR FLOW METER





(a) Perform On-vehicle inspection On-Vehicle Inspection.

(b) Perform Inspection Inspection.

(c) Inspect the function of the mass air flow meter.

(1) Remove the mass air flow meter with the connector connected.

(2) Connect the Techstream to the DLC3.

(3) Turn the ignition switch to ON.

(4) Turn the Techstream on.

(5) Enter the following menus: Powertrain /Engine and ECT / Data List / MAF.

(6) Blow air to the mass air flow meter and check that the intake air amount reading changes.

OK:

The reading changes.

NG -- REPLACE MASS AIR FLOW METER Removal

OK -- REPLACE ECM Removal

5. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)





(a) Disconnect the mass air flow meter meter connector.

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

Standard Resistance:





(c) Reconnect the mass air flow meter meter connector.

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

OK -- REPLACE MASS AIR FLOW METER Removal

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





(a) Disconnect the mass air flow meter meter connector.

(b) Disconnect the ECM connector.

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

Standard Resistance (Check for Open):





Standard Resistance (Check for Short):





(d) Reconnect the mass air flow meter meter connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)

OK -- REPLACE ECM Removal