The Mass Air Flow Sensor (MAFS) is located between the air cleaner assembly and throttle body. The MAFS 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 the load value is out of threshold value, the PCM determines that a fault exists and a DTC is stored.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Rationality check | ● Poor connection ● Air leak in intake system ● Dirty air cleaner ● Faulty MAFS or TPS ● Faulty PCM |
Enable Conditions | ● Engine coolant > 40℃ ● 3℃ < Air Temp. < 45℃ | |
Threshold value | ● Th2(rpm,TPS) > Load value, Ev > Th1(rpm,TPS) | |
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 |
