MAF Sensor In Range But Higher Than Expected
The MAF sensor is reading more air flowing into the engine than the computer expected at that engine speed and load. Think of it like a water meter reporting higher flow than normal—the system detects an anomaly but the sensor is still working within its operating range.
The ECU monitors MAF sensor voltage against expected air mass based on RPM, throttle position, and load. When actual airflow exceeds the predicted value by a calibrated threshold, this fault triggers. The sensor itself is functional and within range, but readings are consistently higher than the mathematical model expects.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| MAF Sensor Voltage | 0.2–5.0V (varies by load) | >Expected voltage for given RPM/load by ~15–25% |
| Calculated Air Mass Flow | ECU-predicted g/s for conditions | 15–25% higher than predicted |
Code P1108 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1108 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.