cannot use the big arm to support the vehicle body.

 2023.07 Doosan DMS-5 Data Monitoring System Diagnostic Software

A phenomenon When the right control handle is pressed down, occasionally the vehicle body cannot be supported. 

 B Inspection Essentials

1. Check whether the posture supporting the car body is correct. The correct posture is: the big and 

small arms meet each other at a 90-degree angle, the left and right control handles are pressed down at 

the same time, and the big and small arms are used to support the car body.

2. Check whether the pilot accumulator is working properly. If the engine does not start, turn the start 

switch to ON and operate the left and right operating handles. If the pressure of all movements can be 

released, it means that the accumulator is working normally.  

3. Check whether the BOOM overload relief valve and main relief valve on the control valve are 

working properly.

 Doosan Diagnostic Tool UVIM Support Doosan Excavators High Quality

4. Check whether the BOOM operates normally when it is lowered.  

5. Check whether the one-way valve inside the BOOM1 valve core on the control valve is damaged.