Komatsu PC850SE-8R Fault Code E0EDA2RMC: Technical Guide

What is Komatsu PC850SE-8R Fault Code E0EDA2RMC?

Fault Code E0EDA2RMC indicates a communication error or data transmission failure within the machine's CAN bus network, specifically affecting the Remote Monitoring Controller (RMC) module. This code signals that the Engine Control Module (ECM) is unable to properly communicate with peripheral control systems or sensors through the Controller Area Network.

The PC850SE-8R relies on continuous data exchange between multiple electronic control units to optimize hydraulic performance, engine efficiency, and emissions control. When communication breaks down, the machine cannot properly coordinate these systems, potentially leading to reduced performance or protective shutdown modes. This is particularly critical in the -8R series, which features advanced KOMTRAX telematics and integrated machine control systems that depend on reliable network communication.

Common Symptoms

When fault code E0EDA2RMC is active, operators typically experience:

• Warning light illumination on the monitor panel, often accompanied by a communication error message
• Intermittent loss of telematics data or inability to access real-time machine information through KOMTRAX
• Reduced engine power or activation of derate mode as a protective measure
• Erratic gauge readings or complete loss of certain display functions on the cab monitor
• Hydraulic system irregularities, including inconsistent response times or reduced flow rates

Potential Causes

The most common technical causes for this fault code in used PC850SE-8R excavators include:

• Corroded or damaged CAN bus connectors, particularly at harness junction points exposed to moisture or debris
• Wiring harness chafing at known rub points near the swing bearing or along the boom structure
• Failed RMC module due to age, vibration damage, or water intrusion in the electrical compartment
• Poor ground connections at the main chassis grounding points, which degrade over time
• ECM software corruption or outdated firmware requiring reprogramming
• Voltage irregularities from aging batteries or failing alternators affecting network stability

How to Troubleshoot and Fix Code E0EDA2RMC

Step 1: Visual Inspection Begin by thoroughly inspecting all CAN bus harness connectors for corrosion, bent pins, or moisture intrusion. Pay special attention to connectors in the engine compartment and near hydraulic components. On used excavators, check for harness wear at pivot points and areas where cables contact metal surfaces.

Step 2: Electrical Testing Using a digital multimeter, verify proper voltage supply (typically 12V or 24V depending on system) to the RMC module. Check CAN High and CAN Low wire resistance between termination points—readings should show approximately 60 ohms across the network with all modules connected. Test ground circuit continuity at all major grounding points.

Step 3: Diagnostic Software Analysis Connect Komatsu diagnostic software (KTEC or equivalent) to retrieve detailed fault data and monitor live CAN bus traffic. Check for additional stored codes that may indicate the source of communication failure. Perform a network integrity test to identify which module is failing to respond.

Step 4: Component Replacement If testing identifies a specific failed component, replace the RMC module, repair damaged wiring harnesses, or clean/replace corroded connectors. For used machines, consider replacing entire harness sections rather than splicing, as aged insulation may fail shortly after repair.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and seek assistance from certified Komatsu technicians for complex electrical diagnostics and repairs.