What is Sany Excavator Fault Code P273?

Fault Code P273 on Sany excavators indicates a malfunction in the Hydraulic Pump Solenoid Circuit, specifically detecting an abnormal voltage or current flow in the pump control system. This diagnostic trouble code (DTC) is generated when the Electronic Control Module (ECM) identifies that the electrical signal to the hydraulic pump's proportional solenoid valve is outside the manufacturer's specified parameters, typically indicating an open circuit, short circuit, or excessive resistance.

This code is critical for Sany excavators because the hydraulic pump solenoid directly controls the flow and pressure of hydraulic fluid throughout the machine. When this circuit malfunctions, the ECM may reduce engine power or limit hydraulic functions to prevent catastrophic damage to the pump assembly or hydraulic system components. For used equipment, this fault often stems from deteriorated wiring or connector corrosion rather than solenoid failure itself.

Common Symptoms

• Reduced hydraulic power across all functions (boom, arm, bucket, swing) or complete loss of hydraulic response
• Engine derate mode activated, limiting RPM to 1200-1500 range to protect the system
• Amber or red warning light illuminated on the instrument cluster, often accompanied by audible alarm
• Erratic hydraulic operation with intermittent loss of power during digging or lifting operations
• Error message displayed on the monitor panel specifically referencing hydraulic system fault

Potential Causes

The most common technical causes for Code P273 on used Sany excavators include:

• Damaged wiring harness between the ECM and hydraulic pump solenoid, particularly at flex points near the pump mounting bracket where vibration causes wire chafing
• Corroded or loose electrical connectors at the solenoid valve terminal, especially on machines operating in wet or coastal environments
• Failed proportional solenoid valve within the hydraulic pump assembly due to internal coil breakdown or mechanical seizure
• ECM internal fault affecting the solenoid driver circuit (less common but possible in high-hour machines)
• Voltage supply issues from damaged main power harness or poor grounding connections at the pump body
• Contaminated hydraulic oil causing solenoid valve sticking, which increases electrical current draw beyond normal parameters

How to Troubleshoot and Fix Code P273

Step 1: Visual Inspection and Connector Check Begin by locating the hydraulic pump solenoid connector on the main pump assembly. Disconnect the connector and inspect both male and female terminals for corrosion, bent pins, or moisture intrusion. On used excavators, this is the most common failure point. Clean connectors with electrical contact cleaner and apply dielectric grease before reconnecting.

Step 2: Electrical Continuity and Resistance Testing Using a digital multimeter, measure the resistance across the solenoid coil terminals with the connector disconnected. Typical resistance values for Sany pump solenoids range from 8-15 ohms. A reading of infinite resistance indicates an open circuit (failed coil), while near-zero resistance suggests a short circuit. Also check for continuity between each solenoid terminal and ground; any continuity indicates unwanted short to chassis.

Step 3: Wiring Harness Inspection Trace the solenoid harness from the pump back to the ECM, paying special attention to areas where the harness passes near moving components or sharp edges. Look for wire insulation damage, particularly at the pump mounting area where engine vibration causes rubbing. For used machines, replace any suspect sections of harness rather than attempting repairs with electrical tape.

Step 4: Voltage Supply Verification With the ignition on but engine off, use your multimeter to verify battery voltage (12-14V) is present at the solenoid connector supply wire. If voltage is absent, trace back toward the ECM to locate the break in power supply. Check all fuses and relays in the main power distribution box related to the hydraulic system.

Step 5: Solenoid Replacement and System Testing If all electrical checks pass but the code persists, the proportional solenoid valve itself has likely failed internally. Replace with genuine Sany parts to ensure proper calibration. After replacement, clear the fault code using Sany diagnostic software or compatible scan tool, then operate the machine through full hydraulic cycles to verify proper function and confirm the code does not return.

Important for Used Equipment: Before replacing expensive components, always address basic maintenance issues first—change contaminated hydraulic oil, check system pressure specifications, and ensure proper ECM grounding at the mounting bolts, as poor grounds cause numerous electrical faults in aging machines.

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Disclaimer: This guide provides general troubleshooting information for experienced diesel mechanics and equipment owners. Always consult the official Sany service manual for your specific model and serial number. If you lack proper diagnostic tools or electrical troubleshooting experience, contact a certified Sany service technician to prevent further damage to electronic components.