Sany SY6HK1 Fault Code U0110(87): Complete Diagnostic Guide

What is Sany SY6HK1 Fault Code U0110(87)?

Fault Code U0110(87) indicates a lost communication error between the Engine Control Module (ECM) and other control modules on the CAN (Controller Area Network) bus system. This is a critical network communication fault that prevents proper data exchange between the engine controller and auxiliary systems like the hydraulic controller, monitor display, or transmission control unit.

In the Sany SY6HK1 excavator, this code specifically points to a CAN bus communication failure affecting the machine's integrated control systems. The CAN network is the digital backbone that allows different electronic modules to share operational data in real-time. When communication breaks down, the ECM cannot coordinate properly with other systems, potentially causing performance limitations, error cascades, or complete operational shutdown. This is particularly critical for used excavators where connector corrosion and wiring harness degradation are common issues.

Common Symptoms

When U0110(87) is active on your Sany SY6HK1, you may experience:

• Multiple warning lights illuminated simultaneously on the instrument cluster, including check engine and system error indicators
• Loss of display functionality on the monitor panel, showing blank screens or frozen data
• Engine derate mode or power limitation as the ECM enters a protective state
• Intermittent or complete loss of hydraulic functions due to communication failure with the hydraulic control module
• Inability to read other diagnostic codes properly through the service tool due to network disruption

Potential Causes

The most common technical causes for U0110(87) in used Sany excavators include:

• Damaged or corroded CAN bus connectors, especially at the ECM, monitor panel, or junction boxes where moisture intrusion is common
• Broken or shorted CAN bus wiring in the main harness, particularly at flex points near the swing bearing or boom pivot areas
• Failed termination resistors on the CAN network (typically 120-ohm resistors at network endpoints)
• ECM power supply issues, including poor ground connections or voltage drops during cranking
• Faulty control modules on the network (hydraulic controller, instrument cluster, or transmission ECU) creating network conflicts
• Aftermarket accessories improperly tapped into the CAN network causing signal interference

How to Troubleshoot and Fix Code U0110(87)

Step 1: Visual Inspection of CAN Bus Connections

Begin with a thorough physical inspection of all CAN bus connectors throughout the machine. Focus on the ECM connector, main junction box near the operator cab, and the instrument panel connections. Look for green corrosion, pushed-back pins, or moisture inside connector housings. On used excavators, pay special attention to harness routing near moving components where abrasion commonly occurs.

Step 2: Test CAN Bus Integrity with Multimeter

Using a digital multimeter, check the CAN-High and CAN-Low lines for proper resistance and voltage. With the key on and engine off, measure between CAN-High and CAN-Low at the ECM connector—you should read approximately 60 ohms (indicating two 120-ohm termination resistors in parallel). Check for 2.5V baseline voltage on each line with key on. Any significant deviation suggests broken termination resistors, short circuits, or open circuits in the network wiring.

Step 3: Isolate Faulty Module or Wiring Section

Disconnect control modules one at a time (starting with non-essential systems like the monitor display) while monitoring if the code clears. This helps identify if a failed module is pulling down the entire network. For used machines, inspect the main harness at known wear points: where it passes through the swing bearing, near hydraulic line bundles, and at the boom base. Look for harness chafing, pinched wires, or previous repair attempts with improper splice techniques.

Step 4: Advanced Diagnostics with Factory Software

Use Sany diagnostic software (or compatible scan tools) to monitor real-time CAN bus traffic and identify which specific module is not responding. The software will show communication status for each network node. If intermittent, perform a wiggle test on harnesses and connectors while monitoring live data to pinpoint loose connections. Check for ECM software updates that may address known communication bugs in older firmware versions.

Step 5: Repair and Verification

Replace damaged wiring harness sections using proper gauge wire and weatherproof connectors rated for mobile equipment. Clean all connector pins with electrical contact cleaner and apply dielectric grease to prevent future corrosion. If replacing a control module, ensure it's programmed correctly for your specific machine configuration. After repairs, clear all codes, cycle the key several times, and operate the machine through full function tests to verify stable communication.

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Disclaimer: This guide provides general diagnostic procedures for Sany SY6HK1 fault code U0110(87). CAN bus systems are complex and require proper diagnostic tools and technical knowledge. For used excavators with extensive electrical modifications or unclear repair history, consult a certified Sany technician or qualified heavy equipment electrician to prevent further damage to expensive control modules.