The Delphi MAF Sensor is an air mass flowmeter, which operates on the principle of hot film anemometry. A heated element is placed within the air stream, and maintained at a constant temperature above the air temperature. The amount of electrical power required to maintain the heated element at the proper temperature is a direct function of the flow rate of the air mass past the element. PCM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
The difference between values coming from the MAF Sensor and those are calculated is analyzed. This difference, or error, is then compared to high and low limit calibration values, which are functions of engine speed. PCM compares MAFS output to calculated flow rate value while enable condition is met.
If the actual air flow is higher than Maximum threshold, or lower than Minimum threshold for more than 75 seconds failure for every 125 seconds test. PCM determines that a fault exists and a DTC is stored. MIL(Malfunction Indicatin Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Compares the difference between MAF Sensor output and calculated flow rate value to a calibration value | ● Poor connection ● Open or short in harness ● Clogged air cleaner ● MAFS ● PCM |
Enable Conditions | ● Barometric Pressure enable conditions criteria met ● Engine Coolant Temperature ≥ 60°C ● 600rpm < Engine Speed < 3000rpm ● Air Conditioning Clutch not transitioning ● Torque Control is not Active ● Traction Control is not Active ● Brake switch is not active ● Current Transmission Torque Converter Clutch State same as previous ● Power Steering is not Cramped ● Engine Speed difference ≤ 300rpm ● TPS value difference ≤ 5% ● MAP value difference ≤ 7 kPa ● Idle Airflow difference ≤ 10% ● Cam phasing control changes ≤ 10% ● MAP/TPS Rationality High Power Condition Fail Criteria Not Met ● MAP/TPS Rationality Low Power Condition Fail Criteria Not Met ● MAP/TPS Rationality Decel. Condition Fail Criteria Not Met ● BARO Update Enable Criteria Met ● Enable Timer ≥ 1.5s | |
Threshold value | ● Comparision result value is out of calibration value | |
Diagnosis Time | ● Continuous (More than 75 seconds failure for every 125 seconds test) | |
MIL On Condition | ● 2 Driving Cycles |
Air Flow (kg/h) | Frequency (Hz) | Air Flow (kg/h) | Frequency (Hz) | Air Flow (kg/h) | Frequency (Hz) |
0 kg/h | 720 ~ 880Hz | 43.2 kg/h | 3,975Hz | 270.0 kg/h | 7,219Hz |
12.6 kg/h | 2,595Hz | 57.6 kg/h | 4,361Hz | 360.0 kg/h | 7,945Hz |
18.0 kg/h | 2,930Hz | 72.0 kg/h | 4,683Hz | 486.0 kg/h | 8,736Hz |
23.4 kg/h | 3,208Hz | 108.0 kg/h | 5,362Hz | 666.0 kg/h | 9,660Hz |
32.4 kg/h | 3,609Hz | 198.0 kg/h | 6,527Hz | 900.0 kg/h | 10,613Hz |
