Actros, SPN 107: clogged filter or a lying sensor
Updated: 2026-11-10
In short. The control unit sees too large a pressure difference across the air filter. Most often the filter really is clogged, but sometimes the tube, connector or the sensor is to blame, so inspect the filter and tubes first and buy a sensor only afterwards.
What the sensor measures
In the SAE J1939 list SPN 107 is Engine Air Filter 1 Differential Pressure; Daimler and Deutz list it the same way. The sensor does not measure air pressure in general but the difference before and after the filter: the dirtier the filter, the larger it is.
| FMI | Meaning |
|---|---|
| 0 | Differential above normal: filter clogged |
| 2 | Signal unstable or erratic |
| 4 | Sensor circuit: voltage below normal or short to ground |
| 3 | Sensor circuit: by the standard voltage above normal or short to positive; Mercedes tables say "open circuit" - verify on the vehicle |
On machines with Cummins engines FMI 15 and 16 also occur ("above normal", different urgency). Open sources have no such data for the Actros.
What the driver sees, and can you drive
Open sources do not say which lamp and message the Actros shows for SPN 107, so do not look for a photo of someone else's icon: check your own vehicle. A scanner, however, shows SPN 107 and FMI. On Multiquip machines with a Hatz engine the same code lit a red lamp and put the engine into reduced-power limp mode; how the Actros behaves, check the manual or a workshop.
Sources give no trigger threshold or permission to drive for the Actros, so the decision stays with the driver. In doubt, stop and check the filter. Power gone or a red lamp on: stay put.
Order of checks
- Recall when the air filter was last changed. If long ago, start there: manufacturer tables advise cleaning or replacing the filter for FMI 0.
- Check for an extra insert filter inside the housing: on Multiquip machines exactly this gave an inflated differential.
- Clamps and pipes between the air filter, turbo and intercooler: any loose ones.
- Connector and harness of the differential sensor: corrosion, moisture, breaks.
- Pressure sampling tubes at the sensor: dry and unblocked.
Measuring the sensor signal and reading the unit are workshop jobs.
What not to do and when to see a workshop
- do not clear the code and drive on without looking at the filter;
- do not replace the sensor until the filter, tubes and connector are checked.
See a workshop if the filter is new and the code returns; if you need the exact meaning of FMI 3 and the trigger threshold for your engine (for example OM 471 or OM 501), which are in Mercedes-Benz diagnostics; or if a red lamp is on or power is lost.
Questions and answers
What does SPN 107 mean on a Mercedes Actros?
Too large a pressure difference across the engine air filter. Most often the filter is clogged, but faulty tubes, a connector or the sensor are possible.
How is FMI 0 different from FMI 3 and 4?
FMI 0 is a differential above normal, i.e. a clogged filter. FMI 3 and 4 are faults in the sensor's electrical circuit; the filter has nothing to do with it.
Can I drive with SPN 107?
Sources name neither a threshold nor permission for the Actros. If power is lost or a red lamp is on, stop. If unsure, check the filter first.
Should I replace the sensor for SPN 107?
Only after checking the filter, the pressure tubes and the connector. The sensor often turns out to be fine.
Code pages on the site
Checked against manufacturer manuals and tables; the same facts as in our videos and articles. The decision to drive remains with the driver.
Cannot find your code? Type it into the search — or paste the whole list from the scanner and we will show which fault is the real one.