Bobcat · Electrical
Bobcat code M4404: Auxiliary controller no communication
What it means
On M-Series loaders, the main controller is not getting messages from the auxiliary controller. Bobcat excavators use this number for a different fault, so check your machine type.
Can I keep running?
Keep going carefully, fix soonUsually, if the machine runs normally: finish the job carefully and fix it soon. Stop if the machine derates, overheats, loses power or the code comes with an alarm.
Check first
- Park on level ground, lower the lift arms and attachment to the ground, stop the engine and remove the key.
- Check battery voltage, then clean and tighten the battery cables and ground straps. Bobcat notes that loose or corroded grounds can set several codes at once.
- Check the fuses and relays for that circuit using the fuse decal or the O&M manual.
- Inspect the connector and harness at the part named in the code for corrosion, water, rubbed-through insulation or pushed-back pins.
- Restart and check whether the auxiliary hydraulics and attachment controls work. If the code returns, call your dealer.
Likely causes
- Low battery voltage or a bad ground
- Blown fuse feeding the auxiliary controller
- Loose, corroded or damaged connector or harness
- Failed auxiliary controller (less common)
The fix
Fixing a power, ground or harness fault clears most cases. If it keeps coming back, a dealer needs to check the controller and data link. Don't run an attachment such as a grapple if its controls act up.
Different code on your screen? Snap the display and Mechy reads it.
Questions
What does Bobcat code M4404 mean?
Auxiliary controller no communication. On M-Series loaders, the main controller is not getting messages from the auxiliary controller. Bobcat excavators use this number for a different fault, so check your machine type.
Can I keep running with M4404?
Usually, if the machine runs normally: finish the job carefully and fix it soon. Stop if the machine derates, overheats, loses power or the code comes with an alarm.
How do I fix Bobcat code M4404?
Fixing a power, ground or harness fault clears most cases. If it keeps coming back, a dealer needs to check the controller and data link. Don't run an attachment such as a grapple if its controls act up.
Sources
Code meanings vary by model, serial range and software. Confirm with your operator's manual or Bobcat dealer before replacing parts.
Snap the display and Mechy reads the code
Take a photo of the screen and the machine, say what it is doing, and get the checks and the fix as steps with moving drawings.
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