What is Sany Excavator Fault Code P375?

Fault Code P375 indicates a malfunction in the hydraulic oil temperature sensor circuit or an abnormal hydraulic oil temperature reading in Sany excavators. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects that the hydraulic oil temperature sensor is sending values outside the expected range, or when the circuit itself shows electrical irregularities such as open circuits, short circuits, or intermittent connections.

The hydraulic oil temperature sensor is critical for protecting your Sany excavator's hydraulic system from overheating damage. When hydraulic fluid exceeds safe operating temperatures (typically above 80-90°C), system efficiency drops dramatically, seal degradation accelerates, and component life shortens significantly. The ECM relies on accurate temperature data to manage cooling fan operation, reduce engine load during high-temperature conditions, and alert operators before catastrophic system failure occurs.

Common Symptoms

• Hydraulic temperature warning light illuminated on the instrument panel or monitor display
• Reduced hydraulic performance including slower cycle times and weak digging force as the system enters protective derate mode
• Cooling fan running continuously at maximum speed regardless of actual operating temperature
• Erratic temperature gauge readings that fluctuate abnormally or display implausible values (extremely high or low)
• Error messages or alarms appearing on the multi-function display indicating hydraulic system issues

Potential Causes

The most common causes of Code P375 in used Sany excavators include:

• Faulty hydraulic oil temperature sensor due to internal element failure or contamination from aged hydraulic fluid
• Damaged wiring harness particularly at flex points near the hydraulic tank where vibration and rubbing cause insulation breakdown
• Corroded or loose electrical connectors at the sensor or ECM connection points, especially common in machines with high hour counts or exposure to moisture
• Contaminated hydraulic oil containing metal particles or water that affects sensor accuracy
• ECM software glitches or calibration drift in older control modules
• Poor ground connections in the sensor circuit causing voltage reference issues

How to Troubleshoot and Fix Code P375

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor typically mounted on the hydraulic tank or return line. Inspect the sensor connector for corrosion, oil contamination, bent pins, or moisture intrusion. Check the wiring harness from sensor to ECM for visible damage, especially at points where the harness contacts the frame or passes through grommets.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance at ambient temperature (typically 2,000-3,000 ohms at 20°C, but verify against Sany specifications). Test the circuit voltage at the harness connector with ignition on—you should see approximately 5 volts reference voltage from the ECM. Check for continuity in all wires and verify proper ground integrity (less than 1 ohm resistance to chassis ground).

Step 3: Component Replacement and Verification If electrical values are out of specification, replace the temperature sensor with a genuine or OEM-equivalent part. For used excavators, always apply dielectric grease to connector pins during reassembly to prevent future corrosion. Clear the fault code using Sany diagnostic software or a compatible scan tool, then operate the machine through several heating cycles to verify the repair. Monitor live data to ensure temperature readings correspond logically with operating conditions.

Disclaimer: This guide provides general troubleshooting information. Always consult your Sany service manual for model-specific procedures and specifications. If you're uncomfortable performing electrical diagnostics, seek assistance from a qualified heavy equipment technician to prevent further damage to electronic systems.