COVER AS-SOUND SUPPRESSION 3501300 - Caterpillar

Charge Valve
During a 100% swing stall operation with fine swing disabled, the swing accumulator should charge to 29 MPa (4206 psi). Swing accumulator oil pressure can be viewed in the monitor from the main menu by selecting "Service", then "Status", then "Hybrid System Status".Note: If the accumulator pressure builds slightly during swing stall, and then quickly drops, the issue is likely excessive SERV leakage. If so, refer to the Troubleshooting, "SERV Leakage Rate - Functional Test". If accumulator pressure does not rise during swing stall, the charge valve is likely not opening up. If suspected that the charge valve is not opening, proceed to the following test steps:
Verify that no diagnostic codes are causing the hybrid system to be disabled. If there are diagnostic codes, work to correct the codes first.
Verify that hybrid system is enabled in the monitor
Verify swing relief high setting
Shutdown machine and ground the implements.
Use a multimeter with a current shunt on the charge valve solenoid to monitor current being sent to the charge valve. Use long leads to the multimeter to allow monitoring from a safe location.
Make sure implements are grounded and surroundings are clear of obstructions
Key on the machine such that the monitor and machine ECMs are powered up but engine is not running. Command 100% swing joystick. Current sent to charge valve should be around 1330mA
If no current is detected during swing stall check resistance of charge solenoid. The resistance of the solenoid should be 5 0.3Ω. If solenoid falls outside of this range, replace the solenoid.
If solenoid resistance is within specifications but no current was detected, inspect harness for shorts.
If current is being supplied to the charge valve in step 7, check pilot pressure supplied to the SERV valve. Shut down machine prior to plumbing pressure gauge to the SERV pilot supply. Pilot pressure should be within the specified range located in Testing and Adjusting, UENR4275, "Relief Valve (Pilot) - Test and Adjust". Use this procedure to adjust pilot pressure if necessary.
Illustration 1 g03368634
Charge Valve Control pressure tap
If current supplied to the charge valve and SERV pilot pressure is within specifications, shut down machine and install a pressure gauge at the charge valve control pressure tap. A noticeable drop in charge PHMV control pressure should be observed on the pressure gauge.
Start machine. Prior to commanding swing stall, charge valve control pressure should be at pilot system pressure. When swing stall is commanded, 1330mA is supplied to the Charge Proportional Hydraulic Modulating Valve (PHMV). If control pressure does not drop when 1330mA is sent to charge the PHMV, the PHMV has likely failed. Replace the PHMV.
If control pressure drops when current is supplied to the charge PHMV, disassemble and inspect the charge valve. If no root cause is observed, reassemble the charge valve and replace the charge PHMV and retry. Discharge Valve
During normal operation the discharge valve will open during aggressive swing acceleration if accumulator is charged above 26 MPa (3770 psi). During swing acceleration the accumulator will discharge down to 26 MPa