Bobcat M0116 (01-16) Fault Code: Air Filter Not Connected
Also shown on the panel as 01-16
Air Filter Not Connected · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M0116 sets when the Bobcat gateway controller sees an open circuit for 30 seconds on the air filter switch signal wire (3700 or 3150 depending on model) with the key switch in run/enter and the engine not running. It points to the air filter switch, its wiring, or the gateway controller, not to a clogged filter by itself. The panel shows this as code 01-16.
Low severity. This code is informational and self resetting. It does not by itself indicate an unsafe operating condition, but an unreliable air filter switch signal means you lose the warning that normally tells you the filter is restricted, so it should be diagnosed before it is ignored long term.
What does Bobcat error code M0116 mean?
M0116, also shown on the panel as 01-16 and described by Bobcat as 'Air Filter Not Connected,' is set by the gateway controller when it detects an open circuit on the air filter switch signal wire. Depending on the machine and harness variant, this signal wire is labeled either 3700 or 3150, with a matching ground wire of 3710 or 2150.
The air filter switch itself is a normally closed switch mounted on the back of the air filter housing. As airflow moves through the filter, it creates vacuum. When that vacuum reaches a critical level, meaning the filter is loaded up enough to restrict airflow, the switch opens. In normal operation this open signal is how the machine tells the operator the filter needs service. M0116 is different: it fires when the controller sees an open circuit condition on the signal wire itself for a sustained period with the key on and the engine off, which points to a wiring or switch problem rather than a legitimately dirty filter.
Bobcat notes that M0116 can appear while the engine is running if the open circuit condition was already present before the engine was started, since the controller checks this circuit at key switch run/enter on.
What triggers a Bobcat M0116 code?
The gateway controller sets M0116 when it detects an open circuit for 30 seconds on the air filter switch signal wire (wire 3700 or wire 3150, depending on model/harness), with the key switch in the run/enter on position and the engine not running.
Common causes of M0116
- A clogged or loaded air filter that has caused the switch to open beyond what the controller expects as a valid signal state.
- An open in signal wire 3700 (or 3150) or its matching ground wire 3710 (or 2150), anywhere between the switch and the gateway controller.
- A failed air filter switch itself, mounted on the back of the air filter housing.
- A fault in the gateway controller.
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, the air filter switch connector, or the mainframe harness connectors.
- An intermittent condition that is not present at the time of testing. Bobcat lists loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these as the probable causes in that case.
How to troubleshoot Bobcat M0116: first checks
- Confirm the key switch is in run/enter on and the engine is not running, since these are the conditions Bobcat lists for the code to set, then check whether the code is active or stored/intermittent.
- Inspect the air filter itself for excessive loading or damage. Even though this code is a wiring/switch fault code rather than a simple 'change your filter' alert, a badly restricted filter can be part of the picture.
- Visually inspect the air filter switch connector, the gateway controller connectors, and the mainframe harness connectors for moisture, corrosion, or pushed-back pins.
- Check continuity on the signal wire (3700 or 3150, depending on your model) and the ground wire (3710 or 2150) from the switch back to the gateway controller, looking for an open circuit.
- Test the air filter switch itself for proper normally closed operation, since it should stay closed until filter vacuum reaches a critical level.
- If the code will not stay active for testing, treat it as intermittent and focus on loose connections, corrosion, and pushed-back pins first, since Bobcat lists these as the most likely causes in an intermittent case.
How the code clears
M0116 is self resetting. No separate clearing step or manual reset procedure is listed for this code; once the open circuit condition is repaired, the controller clears the code on its own.
Affected models and serial ranges
M0116 appears in our records across 16 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-ATZC99999 |
| S530 | SN A7TV11001-99999, SN ATZD11001-99999 |
| S550 | SN A3NK11001-A3NL99999, SN A3NM11001-99999 |
| S570 | SN A7U711001-799999, SN A7U811001-899999 |
| S590 | SN ANMN11001-99999, SN ANMP11001-99999 |
| S630 | SN A3NT12370-99999, SN A3NU11001-11111, SN A3NU11112-99999 |
| S650 | SN A3NV11001-13098, SN A3NV13099-99999, SN A3NW11001-11248, SN A3NW11249-99999 |
| S750 | SN A3P211001-299999 |
| S770 | SN A3P411001-99999 |
| T550 | SN A7UJ11001-AJZV12276 |
| T590 | SN ALJU11001-999999, SN B37811001-999999, SN B3Z711001-999999 |
| T630 | SN A7PU11001-11663, SN A7PU11664-99999 |
| T650 | SN A3P012214-099999, SN A3P111242-199999 |
| T750 | SN ANKA11001-A99999 |
| T770 | SN A3P811001-899999, SN A3P911001-999999 |
| T870 | SN A3PG11001-99999, SN A3PH11001-99999 |
Frequently asked questions
What does Bobcat code M0116 mean?
It means the gateway controller detected an open circuit for 30 seconds on the air filter switch signal wire with the key on and the engine not running. Bobcat's description for this code is 'Air Filter Not Connected.' It points to a wiring, switch, or controller problem, not necessarily a dirty filter.
Is M0116 the same as a dirty air filter warning?
Not exactly. The air filter switch is designed to open when filter vacuum gets high enough to signal a restricted filter, but M0116 fires specifically because the controller sees an open circuit condition on the signal wire itself. A genuinely loaded air filter is one possible cause, but wiring, connector, switch, or controller faults are equally likely.
Why does M0116 show up while the engine is running?
Bobcat notes that this can happen if the open circuit condition was already present before you started the engine. The controller checks the circuit at key switch run/enter on, so if the fault existed at that moment, the code can carry over into engine running.
Do I need to reset M0116 manually?
No. Bobcat lists the clearing condition as self resetting, so once the underlying open circuit is fixed, the code clears on its own without a separate procedure.
Which wires should I check for M0116?
Depending on your specific model and harness, the air filter switch signal wire is either 3700 or 3150, with a matching ground wire of 3710 or 2150. Check both the signal and ground path for an open circuit between the switch and the gateway controller.
What if the code is intermittent and I can't get it to show up during testing?
Bobcat notes that intermittent codes may not have a findable cause at the time of testing. In that case, focus first on loose connections, corrosion, and pushed-back pins in the gateway controller, air filter switch, and mainframe harness connectors, since those are the most commonly cited culprits, along with the controller and wire harness itself.
Which Bobcat machines can show M0116?
This code applies across Bobcat's S510, S530, S550, S570, S590, S630, S650, S750, S770 skid-steer loaders and T550, T590, T630, T650, T750, T770, T870 compact track loaders.