The Mass Air Flow Sensor (MAFS) is located between the air cleaner assembly and the 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 conditions while a small amount of intake air represents deceleration or idle. The mass of intake air should increase at acceleration and be stable during constant engine speed. The ECM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
The ECM compares the actual measured Mass Air Flow signal to the modeled Mass Air Flow value and sets the DTC P0101 when the difference between these two value is too high or too low with lambda deviation in opposite direction.
The modeled Mass Air Flow value is determined by engine speed, throttle angle and ICA valve duty.
ITEM | DETECTING CONDITION | POSSIBLE CAUSE |
DTC Strategy | ● Compare calculated MAF with MAF signal | ● Dirty air cleaner. ● Oil Cap or Dipstick missing or not installed correctly. ● Air leak in intake system ● Contact resistance in connectors. ● Faulty MAFS or TPS |
Enable Conditions | ● 1500〈 Engine speed(RPM)〈 3500 ● 450〈 Measured Mass Air Flow(mg/rev.) 〈1050 ● Coolant temperature 〉 60℃(140℉) | |
Threshold Value | ● Measured MAF/Calculated MAF 〈0.5 or >1.3 | |
Diagnostic Time | ● 120 sec. |
Test Condition | MAF DATA | TPS DATA | ||
Output Voltage (V) | Mass Air Flow (kg/h) | Output Voltage (V) | Resistance (kΩ) | |
Idle | 0.6~1.0 | 11~20 | 0.25~0.80 | 0.71~1.38 |
Idle & A/C "ON" | 1.0~1.3 | 20~30 | - | - |
W.O.T | - | - | 4.0~4.4 | 0.2~3.4 |
