Bobcat T770 aux no com and main no com codes

[landworksTN]

I have a 2020 Bobcat T770 that is giving us a couple of intermittent codes. They don’t always come on at the same time but most of the time they do. M4404 aux no communication and also main controller no communication. I can’t remember the code number right off hand with the main controller. When they come on I have no rabbit on the left joystick and the horn won’t blow as well on the same stick and of course no aux power. We have visibly checked all the fuses, relays, connectors, and the harness and don’t see any obvious issues. Does anyone know what might be the cause of this and would the joystick have anything to do with it? Sometimes the aux no com code will come up by itself but the main controller code only comes up after the aux code comes on. Thanks for any help you may have.

 

[ozarkag]

Bad aux controller. Guaranteed. I have 4 bad ones here to prove it,

 

[landworksTN]

I bet you’re right. Is it the one located under the cab in the center mounted upside down?

 

[ozarkag]

One of two under cab on the machines left side. One is the main frame controller, other one with fewer wires is the aux controller. Will require Bobcat tech to program.

 

[jdkrailroad]

Were you able to fix your T770 with an Aux Controller? I have the same two codes and an additional Left Hand panel code on my S650. Dealer can’t diagnose the issue because it’s intermittent. They are trying to sell me on a new controller and eventually a new harness too.

 

[ozarkag]

If you have the aux no comm code, even if intermittent, that is a failing aux controller. Not so much logic or diagnosis as it's a case of a well known problem.

 

[Skid-steer Repair]

Were you able to fix your T770 with an Aux Controller? I have the same two codes and an additional Left Hand panel code on my S650. Dealer can’t diagnose the issue because it’s intermittent. They are trying to sell me on a new controller and eventually a new harness too.

Sounds like the dealer DID diagnose it.