Driver Unit Capacity Abnormal

Modified on Fri, 9 Feb at 9:36 AM


Applicable Errors: 

84404421 - J1 Driver Unit Capacity Abnormal 

84404422 - J2 Driver Unit Capacity Abnormal 

84404423 - J3 Driver Unit Capacity Abnormal 

84404424 - J4 Driver Unit Capacity Abnormal 

84404425 - J5 Driver Unit Capacity Abnormal 

84404426 - J6 Driver Unit Capacity Abnormal 

84404427 - J7 Driver Unit Capacity Abnormal 

84404428 - J8 Driver Unit Capacity Abnormal 


Error Description: 

 The installed driver unit does not match the connected robot type.


Possible Remedy:  

  • Installed Driver Unit capacity does not match the software value– Install the correct driver unit for the joint generating the error.   
  • Driver Unit failure – Replace Driver Unit  
  • Motion Board failure

Tools and Parts Needed

 Full sized teaching pendant 

#2 Philips screwdriver 

Step by Step Guide

Step 1

Identify the current hardware setting and software setting of the controller.


From main screen navigate to arm → Shift → Maintenance → Driver Unit. 


**Incorrect driver unit setting will be identified by red lettering.

Step 2

Hardware setting can also be confirmed on controller label on top cover of controller. 

Step 3

If there is a mismatch, correct the issue by replacing the affected driver unit. If you are unfamiliar with replacing the driver unit, please contact

Step 4

If the error persists after driver unit replacement, please investigate repair of the controller by contacting

Next Steps:

  • For repair options in the Americas please contact 
  • For repair options outside of the Americas, please contact your local Denso Service Center. 

Owner's Manual Reference

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