Bobcat W3905 (39-05) Fault Code: Left CAN Joystick X-axis Not in Neutral
Also shown on the panel as 39-05 · Also called Left CAN Joystick X-Axis Not in Neutral, Left Joystick X-Axis Not in Neutral
Left CAN Joystick X-axis Not in Neutral · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
W3905 (panel code 39-05) sets when the ACS controller sees the left joystick X-axis out of neutral while PTOL is enabled in H-pattern mode. When it sets, lift and tilt functions are disabled until the condition clears.
Medium severity. The machine does not shut down, but lift and tilt are disabled while the code is active, which stops loader work until the joystick is confirmed in neutral and the fault clears.
What does Bobcat error code W3905 mean?
W3905 is set by the ACS controller when it detects that the left joystick's X-axis is not sitting in the neutral position at the moment PTOL (pilot-operated travel/loader control, as referenced by Bobcat's PTOL term) is engaged. This check only runs when the loader is in H-pattern mode.
Because the lift and tilt functions are disabled while this code is active, the machine is protected from an unintended or uncommanded loader motion input, but the operator loses the ability to run the loader arm until the fault is resolved.
Bobcat notes that this code can also be triggered by a door that is not fully latched, or by opening and closing the door while operating in H-pattern. The rubber boot around the joystick base is also called out: its part number marking must be oriented toward the front of the machine, which suggests boot misalignment or improper installation can hold the joystick out of true neutral or interfere with the sensor reading.
Common causes of W3905
- Rubber boot around the left joystick base is misaligned, damaged, or physically holding the joystick out of neutral, or the operator is holding the joystick out of neutral.
- Door sensor fault, including a door that is not fully latched or that is opened and closed while running in H-pattern mode.
- Left joystick base problem.
- ACS controller fault.
- Moisture, corrosion, or pushed-back pins in the ACS controller connectors, door sensor connector, left joystick connectors, or the ACS wiring harness.
- Intermittent fault not present at time of testing: possible loose connections, corrosion, pushed-back pins, the controller itself, the wire harness, or a combination of these problems.
How to troubleshoot Bobcat W3905: first checks
- :Confirm the left joystick is physically in neutral and nothing (tools, debris, the operator's hand) is holding it off-center.
- Check that the cab door is fully latched. If the door was opened and closed during H-pattern operation, cycle the key and recheck.
- Inspect the rubber boot at the base of the left joystick. Verify the part number marking on the inside of the boot faces the front of the machine, and check for tears, misalignment, or binding that could hold the stick out of neutral.
- Inspect the door sensor and its connector for damage, moisture, or corrosion.
- Inspect the left joystick base and its connectors for looseness, corrosion, or pushed-back pins.
- Inspect the ACS controller connectors and the ACS wiring harness for moisture intrusion, corrosion, or pushed-back pins.
- If the code is intermittent and not present during testing, recheck all connections, pins, and harness routing since the fault may not reproduce on demand.
How the code clears
Bobcat lists the condition for clearing this code simply as PTOL enabled. No separate reset procedure is listed for this code. In practice this means the code clears once the left joystick is confirmed in neutral, the door is fully latched, and PTOL is enabled again in H-pattern mode without the fault condition being detected.
Affected models and serial ranges
W3905 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 ATZC11001-99999 |
| 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 A39511001-99999, 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 W3905 mean?
It means the ACS controller detected that the left joystick's X-axis was not in neutral at the moment PTOL was engaged while the loader was in H-pattern mode. Lift and tilt are disabled until this clears.
Why did W3905 set even though I wasn't touching the joystick?
Bobcat lists a misaligned or damaged rubber boot around the joystick base as a possible cause, since it can physically hold the stick out of neutral. A door that isn't fully latched, or that was opened and closed during H-pattern operation, is also a listed cause.
Will W3905 shut my machine down?
No, but it disables the lift and tilt functions until the fault condition is resolved and the code clears, so loader work stops until you fix it.
How do I clear code W3905 after repairs?
Bobcat's listed clearing condition is simply PTOL enabled. There is no separate reset step listed, so once the underlying cause is fixed and PTOL is enabled again in H-pattern mode without the fault reoccurring, the code should clear.
What should I check first for W3905?
Check that the left joystick is truly in neutral, confirm the door is fully latched, and inspect the rubber boot orientation and condition. These are the simplest, fastest things to rule out before moving to sensor and wiring checks.
Can a bad door sensor cause W3905?
Yes. Bobcat lists the door sensor as a possible cause, and specifically notes that an unlatched door, or opening and closing the door during H-pattern operation, can trigger this code.
Is W3905 an intermittent fault sometimes?
Yes. Bobcat notes that if the code is not active at the time of testing, the cause may not be found immediately. Likely culprits in that case include loose connections, corrosion, pushed-back pins, the controller, or the wire harness.