Sany Excavator Fault Code P220: Complete Diagnostic Guide

What is Sany General Fault Code P220?

Fault Code P220 indicates a malfunction in the hydraulic oil temperature sensor circuit, specifically detecting an abnormal voltage signal or sensor resistance outside the manufacturer's specified range. This code is triggered when the Engine Control Module (ECM) receives voltage readings that fall below 0.2V or exceed 4.8V from the hydraulic oil temperature sensor, suggesting either a short circuit, open circuit, or sensor failure.

This fault is critical for Sany excavators because the hydraulic oil temperature sensor directly affects the machine's ability to protect the hydraulic system from overheating damage. When this sensor fails, the ECM cannot accurately monitor hydraulic temperatures, potentially leading to catastrophic hydraulic pump failure, seal degradation, or system inefficiency that can cost thousands in repairs.

Common Symptoms

• Hydraulic system warning light illuminated on the instrument panel, often accompanied by an audible alarm
• Reduced hydraulic performance or sluggish boom/bucket movements, especially during cold starts
• ECM entering limp mode, limiting engine RPM to 1500-1800 to protect the hydraulic system
• Erratic or frozen temperature gauge readings on the display monitor
• Increased fuel consumption due to ECM applying conservative fuel mapping protocols

Potential Causes

The most common technical causes for P220 on used Sany excavators include:

• Damaged or corroded sensor connector at the hydraulic tank—a known weak point where road debris and moisture accumulate on older machines
• Failed hydraulic oil temperature sensor (thermistor) due to internal element degradation after extended service hours
• Wiring harness chafing near the swing motor mounting bracket, where vibration causes insulation wear
• Broken or shorted wires in the sensor circuit between the hydraulic tank and the main wiring harness
• ECM internal fault (rare, but documented in 2015-2017 model year Sany excavators with software version earlier than V3.2)
• Contaminated hydraulic oil causing sensor element coating and false readings

How to Troubleshoot and Fix Code P220

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor mounted on the hydraulic reservoir tank (typically on the left side near the return filter). Inspect the connector for corrosion, oil contamination, or loose pins. On used excavators, this connector frequently shows green corrosion due to moisture intrusion—clean with electrical contact cleaner and verify pin tension.

Step 2: Resistance Testing Disconnect the sensor connector and measure resistance across the sensor terminals using a digital multimeter. At 20°C (68°F), resistance should read approximately 2,200-2,800 Ohms. At operating temperature (60°C/140°F), expect 280-320 Ohms. Readings outside this range confirm sensor failure requiring replacement (Sany part #60266820).

Step 3: Circuit Voltage Check With the ignition ON and sensor disconnected, check supply voltage at the harness connector. You should measure approximately 5.0V DC on the signal wire (typically orange/black). If voltage is absent or incorrect, trace the wiring harness back to the ECM, checking for breaks, especially where the harness passes through the chassis bulkhead—a common wear point.

Step 4: Harness Inspection for Used Machines On excavators with 5,000+ hours, physically inspect the entire sensor harness for friction wear against metal edges, particularly near rotating assemblies. Use a harness routing diagram from Sany PC-EPC software to verify proper routing and clip placement. Replace any sections showing exposed copper wire.

Step 5: Clear Code and Test After repairs, use Sany diagnostic software or a compatible J1939 diagnostic tool to clear the fault code. Run the machine through a complete warm-up cycle (15-20 minutes) while monitoring live sensor data. The temperature reading should climb smoothly from ambient to 45-65°C during normal operation.

---

Disclaimer: This guide provides general troubleshooting information. Always consult your Sany service manual and consider professional diagnosis for complex electrical issues. Improper repairs may void warranties or cause additional damage.