YOKE 6Y9644 - Caterpillar

Table 1
Related Components: Possible Causes: Recommended Action:
Valve/Lines Left travel pilot control valve failure Refer to Troubleshooting, "Travel Pilot Valve - Functional Test"
Left travel pilot control line failure
Left travel spool is malfunctioning Visually inspect right travel spool in main ACS valve. Travel left and right have unique stems. Verify that correct stem assembly is assembled in travel left and right bores.(1)
Cross over relief failure on left travel motor Refer to Testing and Adjusting, KENR9615, "Relief Valve (Crossover) - Test and Adjust"(1)
Counter balance valve failure on left travel motor Inspect counterbalance valve. Refer to Disassembly and Assembly, UENR0190, "Counterbalance Valve (Travel) - Remove and Install"
Front pump bypass stem malfunction Refer to Troubleshooting, "Bypass Valve (ACS Valve) - Functional Test"
Travel pilot hose is not connected or is leaking Perform a visual inspection of the travel pilot hose
Main relief valve failure Refer to Troubleshooting, "Relief Valve (Main) - Functional Test"
Warm-up valve failure Refer to Troubleshooting, "Hydraulic System Warm-Up - Functional Test"
Electronics/Harness/Solenoids Left travel pilot pressure sensor failure Refer to appropriate diagnostic code troubleshooting procedure
The energize circuit of idler pump bypass Proportional Hydraulic Modulating Valve (PHMV) is shorted to ground Refer to appropriate diagnostic code troubleshooting procedure
Idler pump bypass PHMV solenoid failure Refer to appropriate diagnostic code troubleshooting procedure
Software Straight travel PHMV slope is incorrect Refer to Troubleshooting, "IMV Calibration - Functional Test"(1)
Straight travel PHMV cracking calibration is incorrect
Bypass calibration is incorrect
Pump/Motor/Tank Object or debris jammed between left drive sprocket and track Perform a visual inspection of the left drive sprocket and track
Low hydraulic oil in tank Refer to appropriate diagnostic code troubleshooting procedure
Front pump fails to stroke up Refer to Testing and Adjusting, KENR9615, "Pump Flow Measurement"
Left travel parking brake failure to release Perform a visual inspection of the Left travel parking brake(1)
(1) Denotes Functional Tests that should be considered as a last resort in the troubleshooting process