What is Hitachi Excavator Fault Code E00107804?

Fault Code E00107804 on Hitachi excavators indicates a communication error between the Engine Control Module (ECM) and the Machine Control Unit (MCU), specifically related to CAN bus network timeout or data transmission failure. This diagnostic trouble code (DTC) triggers when the ECM fails to receive expected communication signals from the MCU within the predetermined time interval, typically occurring on the Controller Area Network (CAN) communication line.

This fault is critical for Hitachi excavators because the CAN bus serves as the central nervous system connecting all electronic control units. When communication breaks down, the machine cannot properly coordinate engine performance with hydraulic demands, leading to operational inefficiencies and potential safety concerns. On used machines, this code often surfaces due to age-related deterioration of electrical components rather than catastrophic system failures.

Common Symptoms

• Warning lamp illumination on the instrument cluster, often accompanied by a wrench or diagnostic icon
• Engine derating or power reduction mode, limiting machine to 70-80% of normal output
• Erratic hydraulic response or delayed reaction to joystick inputs due to coordination loss
• Intermittent engine stalling at idle or during load transitions
• Display screen errors showing communication fault messages or blank monitoring data

Potential Causes

The most common technical causes for E00107804 on used Hitachi excavators include:

• CAN bus wiring harness damage at known rub points near the engine mounting brackets or along the boom base where vibration causes insulation wear
• Corroded or moisture-contaminated connectors at the ECM or MCU terminals, particularly on machines operated in high-humidity or coastal environments
• Faulty termination resistors (120-ohm) at either end of the CAN network, leading to signal reflection and data corruption
• ECM or MCU internal failure, though less common than wiring issues in used equipment
• Voltage supply problems providing inadequate power to communication circuits, often traced to aging battery cables or ground connections

How to Troubleshoot and Fix Code E00107804

Step 1: Visual Inspection and Connector Assessment Begin by inspecting all CAN bus harness routing from the ECM (typically located near the engine) to the MCU (usually in the cab area). Look specifically for harness damage where cables pass through bulkheads or contact metal edges. On used excavators, check connector pins for corrosion (green/white deposits) and ensure connector seals are intact. Clean contacts with electrical contact cleaner and apply dielectric grease.

Step 2: CAN Bus Electrical Testing Using a digital multimeter, measure CAN High and CAN Low voltage levels with ignition on, engine off. You should see approximately 2.5V on each line at rest. Check termination resistance by disconnecting both ECM and MCU connectors and measuring between CAN High and CAN Low terminals—you should read approximately 60 ohms (two 120-ohm resistors in parallel). Deviations indicate failed termination resistors or short circuits.

Step 3: Communication Testing with Diagnostic Software Connect Hitachi diagnostic software (Dr.EX or equivalent) to verify real-time CAN bus traffic. Monitor for message error rates and bus-off conditions. If software shows intermittent communication, perform a wiggle test on harnesses while monitoring—movement-induced faults confirm physical wiring damage typical in used machines.

Step 4: Ground Circuit Verification Verify ECM and MCU ground connections have less than 0.5 ohms resistance to battery negative. Poor grounds are frequently overlooked causes of communication errors in aging equipment.

Disclaimer: This guide provides general troubleshooting information. Complex electrical diagnostics should be performed by qualified technicians with appropriate Hitachi diagnostic tools. Always consult the manufacturer's service manual for your specific machine model and serial number.