What is Sany Excavator Fault Code P875?

Fault Code P875 indicates a malfunction in the hydraulic oil temperature sensor circuit or an abnormal hydraulic oil temperature reading exceeding safe operating parameters. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) or Main Controller detects either an electrical fault in the sensor wiring or when hydraulic oil temperature readings fall outside the manufacturer's specified range (typically above 95-100°C or 203-212°F).

This code is critical for Sany excavators because excessive hydraulic oil temperature can lead to rapid seal degradation, reduced hydraulic fluid viscosity, decreased system efficiency, and potential catastrophic failure of hydraulic pumps and motors. The hydraulic system is the lifeblood of excavator operation, and temperature regulation directly impacts machine longevity and performance.

Common Symptoms

When Code P875 is active, operators typically experience:

• Warning light illuminated on the instrument cluster (usually a hydraulic temperature icon or general malfunction indicator)
• Noticeable reduction in hydraulic power and slower cycle times for boom, arm, and bucket functions
• Automatic machine derate or shutdown to protect components once critical temperature thresholds are exceeded
• Audible alarms sounding from the cab when temperature limits are approached
• Hydraulic oil appearing darker or having a burnt odor during visual inspection

Potential Causes

Several factors commonly trigger P875 in used Sany excavators:

• Hydraulic oil temperature sensor failure due to age, contamination, or internal component breakdown
• Damaged or corroded wiring harness and connectors between the sensor and ECM (common wear points near the hydraulic tank mounting)
• Insufficient hydraulic oil levels or use of incorrect viscosity oil for operating conditions
• Hydraulic oil cooler blockage from debris, reducing cooling efficiency
• Faulty cooling fan operation or thermostat malfunction preventing proper heat dissipation
• Excessive system load from worn hydraulic pumps causing heat generation
• Poor electrical ground connections at the sensor mounting point

How to Troubleshoot and Fix Code P875

Step 1: Visual Inspection Check hydraulic oil level using the dipstick—low fluid causes increased temperatures. Inspect the oil cooler fins for debris accumulation and clean thoroughly. Examine the temperature sensor (typically located on the hydraulic tank) for physical damage, oil leaks, or corroded electrical connections.

Step 2: Electrical Testing Using a digital multimeter, disconnect the temperature sensor connector and measure resistance across the sensor terminals. Compare readings against Sany specifications (typically 200-400 ohms at 20°C). Check for voltage supply at the harness connector (usually 5V reference voltage). Inspect wiring for chafing, especially where harnesses contact frame members—a common issue in used machines.

Step 3: Sensor and System Verification If electrical readings are correct, use Sany diagnostic software to monitor real-time temperature values. Compare sensor readings with an infrared thermometer measurement of actual hydraulic oil temperature. Replace the temperature sensor if readings differ by more than 5°C. Verify cooling fan operation and thermostat function before clearing codes.

For used excavators, always inspect connector seals and apply dielectric grease to prevent moisture intrusion—a frequent cause of intermittent sensor faults.

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Disclaimer: This guide provides general troubleshooting information. Always consult your Sany service manual and qualified diesel technicians for machine-specific procedures and safety protocols.