Sany Excavator Fault Code P347: Complete Diagnostic Guide

What is Sany General Fault Code P347?

Fault Code P347 indicates a malfunction in the hydraulic pump solenoid control circuit, specifically detecting an abnormal voltage signal or open circuit condition in the pump flow control system. This code is triggered when the Electronic Control Module (ECM) detects that the electrical signal to the hydraulic pump's proportional solenoid valve is outside the manufacturer's specified range (typically 0.5-4.5 volts).

This fault is critical for Sany excavators because the hydraulic pump solenoid directly controls hydraulic flow rates and system pressure. When this circuit malfunctions, the machine cannot properly regulate hydraulic power distribution to the boom, arm, bucket, and swing functions, severely impacting operational efficiency and potentially causing damage to downstream hydraulic components.

Common Symptoms

When Code P347 is active on your Sany excavator, you may experience:

• Hydraulic system derate or complete loss of hydraulic function across multiple circuits
• Illuminated warning light on the instrument cluster with reduced engine power
• Erratic or sluggish hydraulic responses during multi-function operations
• Abnormal hydraulic pump noise or fluctuating system pressure readings
• Engine automatically limiting RPM to protect the hydraulic system from overpressure conditions

Potential Causes

The most common technical causes for P347 in used Sany excavators include:

• Damaged or corroded wiring harness between the ECM and hydraulic pump solenoid (especially at flex points near the pump mounting area)
• Failed proportional solenoid coil within the hydraulic pump assembly due to overheating or moisture intrusion
• Loose or corroded electrical connectors at the pump solenoid or ECM connection points
• Shorted wiring caused by harness rubbing against frame components or hydraulic lines
• ECM internal fault affecting the solenoid driver circuit (less common but possible in high-hour machines)
• Low voltage supply to the solenoid due to failing alternator or battery connection issues

How to Troubleshoot and Fix Code P347

Step 1: Visual Inspection Begin by disconnecting the battery and thoroughly inspecting the wiring harness from the ECM to the hydraulic pump solenoid. On used excavators, check for obvious damage, chafing, or corrosion at connector pins. Pay special attention to harness routing near the pump—this is a known wear point on Sany machines.

Step 2: Electrical Testing Using a digital multimeter, measure the solenoid coil resistance at the pump connector (disconnect first). Specifications typically range between 3-8 ohms; readings outside this range indicate solenoid failure. Next, check for continuity along the entire harness length and verify no shorts to ground.

Step 3: Voltage Supply Check Reconnect the harness and measure supply voltage at the solenoid connector with the ignition on (engine off). You should see battery voltage (12-14V). If voltage is absent, trace back to the ECM and check related fuses and relays.

Step 4: Advanced Diagnostics Connect Sany-compatible diagnostic software (SY Diagnostic Tool or equivalent) to monitor real-time solenoid command signals from the ECM. Compare commanded versus actual values. A significant deviation indicates either wiring issues or ECM problems.

Step 5: Component Replacement For used excavators, if wiring and connectors check out, replace the hydraulic pump solenoid assembly. Before installation, apply dielectric grease to all connectors to prevent future corrosion. Clear codes and perform a complete system function test.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sany service manual for your specific model and serial number. Complex hydraulic and electrical diagnostics should be performed by certified technicians with proper tools and safety equipment.