Sany Excavator Fault Code P507: Complete Diagnostic Guide

What is Sany Excavator Fault Code P507?

Fault Code P507 indicates a Main Relief Valve Solenoid Circuit Malfunction in Sany excavators. This code triggers when the Electronic Control Module (ECM) detects an abnormal electrical signal—either an open circuit, short circuit, or incorrect voltage—in the wiring or solenoid that controls the main relief valve in the hydraulic system.

The main relief valve solenoid regulates maximum system pressure to prevent hydraulic component damage and optimize fuel efficiency. When this circuit fails, the excavator cannot properly modulate hydraulic pressure, which directly impacts digging force, swing speed, and overall machine performance. For used Sany excavators, this fault often stems from age-related electrical degradation rather than mechanical valve failure.

Common Symptoms

When Code P507 is active, operators typically experience:

• Reduced hydraulic power across all functions (boom, arm, bucket, swing)
• Illuminated warning light on the instrument cluster, often accompanied by an audible alarm
• Erratic hydraulic performance with inconsistent pressure delivery during operation
• Engine derating in some models, limiting RPM to protect the hydraulic system
• Sudden loss of breakout force when digging in hard materials

Potential Causes

The most common technical reasons for P507 in used Sany excavators include:

• Damaged wiring harness near the main pump area where vibration and heat cause insulation breakdown
• Corroded electrical connectors on the solenoid due to moisture ingress (common in machines operated near water)
• Failed relief valve solenoid coil with open or shorted windings (typical after 5,000+ operating hours)
• Loose or damaged pins in the ECM connector affecting signal transmission
• ECM software glitches requiring calibration updates (less common but documented in 2015-2018 models)
• Hydraulic oil contamination causing the solenoid spool to stick, increasing electrical resistance

How to Troubleshoot and Fix Code P507

Step 1: Visual Inspection Begin by examining the relief valve solenoid located on the main hydraulic pump. Check for physical damage, oil leaks, or burned connectors. On used excavators, inspect the wiring harness for rub points against the pump housing or frame—this is a known failure point on Sany models.

Step 2: Electrical Testing Disconnect the solenoid connector and use a multimeter to check coil resistance. Standard resistance should be 10-15 ohms (consult your specific service manual). Also measure voltage supply from the ECM with ignition on—it should read 12-14 volts DC. Check for continuity in all wiring back to the ECM.

Step 3: Advanced Diagnostics Connect Sany diagnostic software (or compatible OBD scanner) to monitor real-time solenoid command versus actual response. Check for corrosion inside connectors by spraying electrical contact cleaner and inspecting pins. For used machines, replacing the entire pigtail harness to the solenoid often resolves intermittent faults more reliably than individual wire repairs.

Step 4: Component Replacement If testing confirms solenoid failure, replace with a genuine Sany part to ensure proper PWM (Pulse Width Modulation) response. After replacement, clear codes and perform a hydraulic pressure calibration using diagnostic software.

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Disclaimer: This guide provides general technical information. Hydraulic and electrical systems operate under high pressure and voltage. Always consult a certified heavy equipment technician and refer to your specific Sany service manual before performing repairs on used excavators.