What is Sany Excavator Fault Code E105?

Fault Code E105 on Sany excavators indicates a Hydraulic Pilot Pressure Sensor Circuit Malfunction or abnormal pressure reading in the pilot hydraulic system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects voltage signals from the pilot pressure sensor that fall outside the manufacturer's specified range (typically 0.5-4.5V). The pilot pressure system is critical for controlling the excavator's hydraulic functions—including boom, arm, bucket, and swing operations—making this code a priority concern for operational safety and machine productivity.

In Sany excavators, the pilot hydraulic circuit uses low-pressure oil to control high-pressure main hydraulic functions. When the ECM cannot accurately read pilot pressure data, it may limit machine functions or enter a protective derate mode to prevent damage to hydraulic components or erratic machine behavior.

Common Symptoms

• Hydraulic function sluggishness or complete loss of certain operations (boom, stick, or swing may not respond properly)
• Warning light illuminated on the instrument cluster, often accompanied by an audible alarm
• Reduced machine performance or entry into limited-function mode (safety derate)
• Erratic joystick response where control inputs don't match hydraulic output consistently
• Intermittent faults that appear and disappear, especially during cold starts or after extended operation

Potential Causes

The most common technical causes for Code E105 on used Sany excavators include:

• Faulty pilot pressure sensor due to internal component degradation or contaminated hydraulic oil causing sensor drift
• Damaged wiring harness or connector corrosion, particularly at the sensor plug near the pilot valve assembly (a known wear point from vibration and heat exposure)
• Low pilot hydraulic oil pressure caused by clogged pilot filters, worn pilot pump, or internal leakage in the pilot circuit
• ECM communication issues or poor grounding connections affecting signal integrity
• Contaminated hydraulic fluid with metal particles or water intrusion affecting sensor accuracy
• Voltage supply problems from the main electrical harness providing inconsistent power to the sensor (should be approximately 5V reference)

How to Troubleshoot and Fix Code E105

Step 1: Visual Inspection and Connector Check Begin by inspecting the pilot pressure sensor located near the pilot control valve block. Disconnect the electrical connector and examine for corrosion, bent pins, or moisture intrusion—common issues in used excavators. Clean contacts with electrical contact cleaner and apply dielectric grease before reconnecting.

Step 2: Electrical Testing with Multimeter Using a digital multimeter, check the reference voltage at the sensor connector with the key on, engine off (should read approximately 5V). Test sensor output voltage while manually increasing pilot pressure if possible (voltage should range smoothly from 0.5V to 4.5V). Check harness continuity from sensor to ECM and verify proper ground resistance (less than 5 ohms).

Step 3: Hydraulic System Verification Check pilot hydraulic oil level and condition—contaminated or low oil can cause erratic sensor readings. Replace the pilot filter if not recently serviced. Use a hydraulic pressure gauge to verify actual pilot pressure (typically 30-40 bar/435-580 psi at idle) matches sensor output voltage.

Step 4: Component Replacement If wiring and hydraulic pressure are confirmed normal, replace the pilot pressure sensor with a genuine Sany or quality aftermarket unit. On used machines, also inspect the wiring harness routing for rub points against metal edges or heat sources—reroute and secure with new protective loom if necessary.

Step 5: Clear Codes and Verify After repairs, use Sany diagnostic software or compatible scan tool to clear fault codes. Operate the machine through full hydraulic cycles and monitor for code recurrence.

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Disclaimer: This guide provides general troubleshooting information for Code E105. Hydraulic and electrical system repairs should be performed by qualified technicians with proper safety equipment. Always consult the official Sany service manual for your specific excavator model and serial number range before performing repairs.