Sany Excavator Fault Code 45: Complete Diagnostic Guide

What is Sany Excavator Fault Code 45?

Fault Code 45 on Sany excavators indicates a malfunction in the hydraulic pump pressure sensor circuit or an abnormal hydraulic system pressure reading. This code is triggered when the Electronic Control Module (ECM) detects that the hydraulic pressure sensor signal is outside the expected voltage range or when actual system pressure deviates significantly from commanded pressure.

This fault is critical because Sany excavators rely on precise hydraulic pressure monitoring to regulate pump output, prevent system overloading, and protect components from damage. When Code 45 activates, the machine may enter a derate mode to prevent catastrophic hydraulic system failure, directly impacting productivity and operational safety.

Common Symptoms

When Fault Code 45 is active, operators typically experience:

• Warning light illumination on the instrument cluster (usually amber or red hydraulic icon)
• Reduced hydraulic performance including slow boom, arm, or bucket movements
• Engine derate where the ECM limits engine RPM to protect the hydraulic system
• Erratic hydraulic function with inconsistent actuator speeds or jerky movements
• Audible alarm from the cab warning system in some Sany models

Potential Causes

The most common technical causes for Code 45 in used Sany excavators include:

• Faulty hydraulic pressure sensor – internal sensor element failure or contamination from hydraulic fluid degradation
• Damaged wiring harness – particularly at known rub points near the main pump housing where cables contact the rotating group
• Corroded or loose electrical connectors – moisture intrusion in the sensor connector (common on older machines with worn seal boots)
• ECM communication errors – software glitches or ground circuit issues affecting signal integrity
• Actual hydraulic system problems – worn main pump, blocked filters, or relief valve malfunctions causing genuine pressure anomalies

How to Troubleshoot and Fix Code 45

Step 1: Visual Inspection Begin by inspecting the hydraulic pressure sensor (typically mounted on the main pump body). Check for physical damage, fluid leaks, and connector integrity. On used excavators, carefully examine the wiring harness for abrasion points, especially where it routes near moving components or sharp edges.

Step 2: Electrical Testing Using a digital multimeter, check the sensor supply voltage (should be 5V ±0.25V with ignition on). Measure sensor signal output voltage while monitoring system pressure with a mechanical gauge. Compare readings to Sany specifications (typically 0.5-4.5V range). Test harness continuity and verify ground circuit resistance is below 5 ohms.

Step 3: Diagnostic Software Analysis Connect Sany-specific diagnostic software or a compatible J1939 scan tool to monitor live sensor data. Compare commanded versus actual pressure readings. Check for intermittent signal dropouts that indicate poor connections or internal sensor failures common in machines with high operating hours.

Step 4: Component Testing and Replacement If electrical tests pass but the code persists, perform a hydraulic pressure test at the sensor port using calibrated gauges. Replace the pressure sensor if readings are erratic. On used equipment, always clean connector pins with electrical contact cleaner and apply dielectric grease before reassembly to prevent future corrosion.

---

Disclaimer: This guide provides general diagnostic information. Always consult the official Sany service manual for your specific model and consider professional assistance for complex hydraulic or electrical repairs.