The mass air flow sensor (MAF) is located between the air cleaner assembly and throttle body. The MAF uses a hot film type sensing element to measure the mass of intake air entering the engine. This hot film type air flow sensor consists of a hot film sensor, housing and metering ducts. Mass air flow rate is measured by detection of heat transfer from a hot film probe. The change in air flow rate causes change in the amount of heat being transferred from the hot film probe surface to the air. A large amount of intake air represents acceleration or high load condition while a small amount of intake air represent decceleration or idle. The mass of intake air should increase at acceleration and be stable during constant engine speed. The PCM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
If MAF output voltage is lower than 1.055 V, the PCM determines that a fault exists and a DTC is stored.
Item
Detecting Condition
Possible cause
DTC Strategy
? Output voltage is monitored
? Poor connection
? Open or short to ground in MAF circuit
? Dirty air cleaner
? Faulty MAF
? Faulty PCM
Enable Conditions
? Engine speed > 400rpm
Threshold value
? Output voltage < 1.055V
Diagnosis Time
? Continuous
MAFS
Normal Parameter
Approx. 700RPM(Idle)
Approx. 2000RPM
Approx. 3000RPM
Signal Voltage
0.6 ~ 1.0V
1.3 ~ 1.5V
1.7 ~ 1.9V
Mass Air Flow
11.66 ~ 15.38kg/h
28.41 ~ 35.38kg/h
43.84 ~ 53.38kg/h