CAP 0814586 - Caterpillar

Illustration 1 g03368382
(A) CHECKED valve position
(B) CLOSED valve position
(C) OPEN valve position
(1) Rear Pump
(2) Passage to stick IMV
(3) Flow combiner spool
(4) Flow combiner PHMV
(5) Passage to boom and bucket IMV
(6) Front Pump
Run flow combiner on machine calibration prior to troubleshooting combiner.
If combiner fails calibration, check for diagnostic codes. If a code is present, work to clear the code prior to continuing with combiner troubleshooting.
Verify that the bypasses are functioning correctly using the procedures contained in this document.
Shut off the engine by turning the start switch to the "OFF" position. Ground the implements and perform a System Pressure Release procedure. Refer to Testing and Adjusting, UENR7018, "System Pressure - Release". Place a current shunt on the combiner PHMV solenoid. Use long leads on the digital multi-meter to allow the reading to be monitored from a safe position.
With the machine shut off, install a pressure gauge to combiner control pressure tap shown in the following image. Use a long hose so the combiner control pressure can be monitored from a safe location.
Start machine, verify that no current is being sent to the combiner PHMV. Combiner control pressure should currently be at pilot system pressure. If not, adjust the pilot system pressure as specified in Testing and Adjusting, UENR7018, "Gear Pump (Pilot) - Test".
Use the machine monitor to send a current override to the combiner PHMV. Command 2 Amps. Verify multi-meter reads 2 amps. If not, there may be an issue with the harness or the PHMV solenoid. Resistance of the PHMV solenoid should be 5 0.3 Ω.
When 2 amps are sent to the combiner PHMV, the control pressure should drop to near zero. If the control pressure does not drop when a 2 amp override is sent to combiner PHMV, then the PHMV has likely failed. Replace the combiner PHMV and retry.
Illustration 2 g03583685
(7) Flow combiner PHMV
(8) Combiner control pressure tap
Shut down the machine and remove the current shunt and combiner control pressure gauge prior to continuing troubleshooting. Replace the plug-in combiner control pressure tap. Remove all Cat® Electronic Technician (Cat ET) Service Tool current overrides prior to continuing.
Perform the following tests to verify that the combiner valve reaches each of the three positions.
Closed Position (B above)
Verify that all line reliefs and main relief is properly set.
When the combiner is in the closed position, pump 1 (boom/bucket) and pump 2 (stick/swing) are isolated from each other. To test this condition, the following test can be performed.
Stall bucket with 100% lever while swinging with 100% lever. Pump 1 should reach 35 MPa while pump 2 will remain under 8 MPa for steady state swing speed.
Open position (C above)
Verify that all line reliefs and main relief is properly set.
Check boom up cycle time as specified in test and