Mass Air Flow Sensor
The analog MAF sensor uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool. This hot wire is maintained at 200°C (392°F) above the ambient temperature as measured by a constant cold wire. The current required to maintain the temperature of the hot wire is proportional to the mass air flow. The MAF sensor then outputs an analog voltage proportional to the intake air mass.
The MAF sensor is located between the air cleaner and the throttle body or inside the air cleaner assembly. Most MAF sensors have integrated bypass technology with an integrated IAT sensor. The hot wire electronic sensing element must be replaced as an assembly. Replacing only the element may change the air flow calibration.
For the 2011 MY, some vehicles will use a digital MAF sensor, which outputs a frequency proportional to the intake air mass. The digital input low level driver software sets a flag to indicate that the frequency is out of range and a flag to indicate a high or low state. Low corresponds to 1.5 KHz and 6.6 kg/hr and high corresponds to 12 KHz and 982 kg/hr.
The Mass Air Flow sensor can produce values near zero when the engine has stalled or when the manifold empties during transient tip outs. The rpm logic is used to prevent setting a P0102 when the engine is stalling or during tip out conditions and the MAF reading is low but the sensor has not failed.
| DTCs | Analog Sensor: P0102 (low input), P0103 (high input) Digital MAF Sensor A: P0100 (broken element), P0102 (low input), P0103 (high input), P0104 (intermittent) Digital MAF Sensor B: P010A (broken element), P010C (low input), P010D (high input), P010E (intermittent) |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds to register a malfunction |
| Entry Condition | Minimum | Maximum |
| P0100 | ||
| Time since last PIP edge (engine has not stalled) | ||
| P0102 | ||
| Time since last PIP edge (engine has not stalled) | 150 msec | |
| Engine RPM | Base idle speed - 25 rpm | |
| Relative Throttle position | 1 degree | |
| P0103 | ||
| Engine RPM | 6000 rpm |
| Analog Sensor: P0102 - Voltage < 0.244 volts and engine running P0103 - Voltage > 4.785 volts engine rpm < 4, 000 rpm Digital Sensor: P0100 - MAF sensor signal period > 1300 microseconds (< 0.78 kHz) for > 1 sec P0102 - MAF sensor signal period > 658 microseconds (< 1.5 kHz) for > 1 sec P0103 - MAF sensor signal period < 83 microseconds (> 0.78kHz) for > 1 sec P0104 - MAF sensor open/shorted > 25 occurences |