P0103

DESCRIPTION
The Mass Air Flow (MAF) Sensor is located in the air cleaner. The sensor measures the mass of air passing though the air intake and generates a pulsed signal. The Engine Control Module (ECM) counts the pulses generated by the sensor and uses the signal to set fuel injector base pulse width and ignition timing.
To operate, the MAF sensor requires battery voltage at sensor terminal 3 and ground at sensor terminals 1 and 2. As air passes through the sensor, the sensor generates pulses at sensor terminal 4. The frequency of the pulses increases as mass air flow increases.





FAILURE CONDITIONS
The ECM will set P0102 / P0103 and the Malfunction Indicator Lamp (MIL) will turn on if the MAF sensor output indicates an open circuit, or less than 0.5 grams/second for 0.5 seconds with an engine speed greater than 200 RPM during two driving cycles. This code indicates an unusually low air flow rate being read by the MAF sensor or ECM. The ECM will set P0103 and the Malfunction Indicator Lamp (MIL) will turn on if the engine is running and the MAF sensor output indicates more than 2 grams/second for 0.5 seconds during two driving cycles. This code indicates an unusually high air flow rate is being read by the MAF sensor or ECM.

Part 1 Of 2:

Part 2 Of 2:

TEST PROCEDURE















HARNESS INSPECTION PROCEDURES

TROUBLESHOOTING HINTS
1. If the engine stalls occasionally, start the engine and shake the MAF sensor harness. If the engine stalls, check for poor contact at the MAF sensor connector.
2. If the MAF sensor output voltage is other than 0 when the ignition switch is turned on (do not start the engine). Check for the faulty MAF sensor or ECM.
3. If the engine can be idle even if the MAF sensor output voltage is out of specification, check for the following conditions;
- Disturbed air flow in the MAF sensor, disconnected air duct, and clogged air cleaner filter.
- Poor combustion in the cylinder, faulty ignition plug, ignition coil, injector, and incorrect comparison.
4. Though no MAF sensor malfunction occurs, check the mounting direction of MAF sensor.






USING VOLTMETER

NOTE:
1. When the vehicle is new [within initial operation of about 500 km (300 miles)], the mass air flow sensor air quantity will be about 10% higher.
2. Use an accurate digital voltmeter.
3. Before checking, warm up the engine until the engine coolant temperature reaches 80 to 90 °C (176 to 198 °F).