Sany Excavator Fault Code P622: Complete Diagnostic Guide

What is Sany General Fault Code P622?

Fault Code P622 indicates a malfunction in the hydraulic pump solenoid valve circuit, specifically detecting an abnormal voltage or current condition in the pump control system. This code is triggered when the Electronic Control Module (ECM) detects an open circuit, short circuit, or resistance value outside the manufacturer's specified range in the solenoid valve wiring or the valve itself.

In Sany excavators, the hydraulic pump solenoid valve regulates hydraulic flow and pressure based on operator input and engine load conditions. When this circuit fails, the machine cannot properly modulate hydraulic power, directly impacting operational efficiency and potentially causing the excavator to enter a protective derate mode to prevent further damage.

Common Symptoms

When Code P622 is active, operators typically experience:

• Warning light illumination on the instrument cluster, often accompanied by a continuous or intermittent alarm
• Reduced hydraulic power or sluggish response from boom, arm, and bucket functions
• Inconsistent engine rpm fluctuations under load due to improper pump control
• Failure to enter high-flow mode when demanded, limiting productivity
• ECM-initiated power derate, restricting engine output to protect the hydraulic system

Potential Causes

The most common technical causes for P622 in used Sany excavators include:

• Damaged or corroded wiring harness at known rub points near the pump mounting bracket or undercarriage routing
• Failed hydraulic pump solenoid valve due to internal coil breakage or contamination from hydraulic fluid ingress
• Connector corrosion at the solenoid valve plug or ECM connection points, especially in machines operated in wet conditions
• Shorted wiring caused by harness chafing against metal surfaces during boom or swing operations
• ECM internal fault (less common) affecting the solenoid driver circuit
• Voltage supply issues from the main power relay or corroded ground connections

How to Troubleshoot and Fix Code P622

Step 1: Visual Inspection
Begin by inspecting the wiring harness from the ECM to the hydraulic pump solenoid valve. Look for obvious damage, worn insulation, or connectors with corrosion—particularly critical in used excavators with 3,000+ hours. Check harness routing near moving components and sharp edges.

Step 2: Electrical Testing
Using a digital multimeter, disconnect the solenoid valve connector and measure resistance across the solenoid coil terminals. Typical specifications for Sany solenoids range from 10-30 ohms; consult your service manual for exact values. Next, check for voltage supply (typically 12-24V) at the harness connector with the ignition on.

Step 3: Harness and Ground Verification
Test continuity from the ECM connector to the solenoid valve plug to identify open circuits. Verify the ground circuit integrity by measuring resistance to chassis ground (should be less than 1 ohm). Clean all connector pins with electrical contact cleaner and apply dielectric grease.

Step 4: Component Replacement
If resistance or voltage values fall outside specifications, replace the faulty solenoid valve or repair damaged wiring sections. For used machines, consider replacing the entire harness segment if multiple repairs have been made previously. After repairs, clear the fault code using Sany diagnostic software or a compatible OBD scanner and perform an operational test.

Disclaimer: This guide provides general diagnostic procedures. Always consult the official Sany service manual for your specific model and serial number. Complex electrical issues should be diagnosed by certified heavy equipment technicians with access to factory diagnostic tools.