Bobcat M0311 (03-11) Fault Code: Battery Voltage Extremely High
Also shown on the panel as 03-11 · Also called Battery Voltage Extremely, System Voltage Extremely High
Battery Voltage Extremely High · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M0311 sets when the gateway controller sees battery voltage above 18 volts on the un-switched power wires 1110 and 1130, with the key switch on and engine rpm below 1500 rpm. It shows in the panel as code M0310 "battery voltage high" while M0311 itself is a stored, software-only code. The seat bar, lift and tilt, and parking brake LEDs plus the battery icon will flash when it is active.
High severity. Extremely high battery voltage can damage the controller, lighting, and other low-voltage components on the machine if it is not tracked down. The code self-resets once voltage drops back into range, but the underlying charging or wiring problem needs to be fixed before it recurs or causes damage.
What does Bobcat error code M0311 mean?
M0311 means the gateway controller measured battery voltage greater than 18 volts on the un-switched power supply wires 1110 and 1130. This is well above normal charging voltage, so the controller flags it as an extreme high-voltage condition rather than a routine high-voltage warning.
When this happens, the operator will see the seat bar, lift and tilt, and parking brake LEDs flashing along with the battery icon. The panel itself will not display "M0311": instead it shows code M0310 "battery voltage high" in the left hand panel, while M0311 is logged only in diagnostic software as a stored code.
This code is tied closely to code M4110 "alternator voltage high." If the alternator is overcharging the battery, M0311 is the machine's way of flagging that the voltage reaching the un-switched circuits has gone past a safe threshold.
What triggers a Bobcat M0311 code?
The controller sets M0311 when the key switch is in the run/enter (on) position, engine rpm is below 1500 rpm, and battery voltage on wires 1110 and 1130 is measured above 18 volts.
Common causes of M0311
- Code M4110 "alternator voltage high" already active, pointing to an overcharging alternator or regulator problem.
- A fault in the gateway controller itself.
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, the alternator connector, the engine harness, or the mainframe harness.
- Loose connections, corrosion, or pushed-back pins anywhere along the wiring path, sometimes in combination with each other.
- An intermittent condition: if the code is not active at the time of testing, the exact cause may not be found. Likely culprits are the same as above, loose connections, corrosion, pushed-back pins, the controller, or the wire harness, alone or combined.
How to troubleshoot Bobcat M0311: first checks
- Check for an active or stored code M4110 "alternator voltage high" first, since this is directly linked to M0311.
- Inspect the gateway controller connectors, the alternator connector, the engine harness, and the mainframe harness for moisture, corrosion, or pins that have been pushed back out of their sockets.
- Check all related connections for looseness or corrosion, since these are listed as probable causes on their own and in combination with other issues.
- With the key switch on and engine rpm below 1500 rpm, check battery voltage on the un-switched power wires 1110 and 1130 to confirm whether it is currently reading above 18 volts.
- If no fault is found and the code is not currently active, treat it as intermittent: recheck all connectors and harness sections for the same corrosion, looseness, or pushed-back pin issues, since an intermittent code may not show a cause at the time of testing.
How the code clears
M0311 is self resetting. No separate clearing step is listed, meaning once battery voltage drops back within the acceptable range, the code clears on its own. Repairing the underlying alternator, controller, or wiring issue is still necessary to prevent it from setting again.
Affected models and serial ranges
M0311 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 M0311 mean?
It means the gateway controller detected battery voltage above 18 volts on the un-switched power wires 1110 and 1130 while the key switch was on and engine rpm was below 1500 rpm. It signals an extremely high system voltage condition.
Why does my panel show M0310 instead of M0311?
M0311 is a stored code that only shows up in diagnostic software. When it occurs, the panel displays the related code M0310 "battery voltage high" instead, along with flashing seat bar, lift and tilt, and parking brake LEDs and the battery icon.
Is M0311 related to the alternator?
Yes. One of the listed causes is code M4110 "alternator voltage high." If the alternator or its regulator is overcharging the battery, that can push voltage past 18 volts on wires 1110 and 1130 and trigger M0311.
Do I need to manually clear M0311?
No. It is a self resetting code. Once battery voltage returns to a normal range, the code clears on its own. No separate clearing procedure is listed.
Can corrosion or bad connectors really cause a voltage code like this?
Yes. Moisture, corrosion, or pushed-back pins in the gateway controller connectors, alternator connector, engine harness, or mainframe harness are all listed as possible causes, either alone or combined with loose connections.
What if the code won't come back when I test the machine?
That is treated as an intermittent condition. If M0311 is not active at the time of testing, the exact cause may not be identifiable right then. Likely causes are still loose connections, corrosion, pushed-back pins, the controller, or the wire harness.
Is it safe to keep operating with M0311 stored?
Extremely high battery voltage can stress the controller and other electrical components. Even though the code self-resets, the charging system or wiring issue behind it should be diagnosed and repaired before continuing regular operation.