Komatsu PC850SE-8R Fault Code E10CA115: Complete Diagnostic Guide

What is Komatsu PC850SE-8R Fault Code E10CA115?

Fault Code E10CA115 indicates a communication error or abnormal signal detected in the machine's CAN (Controller Area Network) communication system, specifically related to data transmission between the engine controller (ECM) and other electronic control units.

This code typically signals that the ECM is unable to properly communicate with peripheral controllers, such as the hydraulic control unit, monitor panel, or transmission controller. In the PC850SE-8R, this communication network is critical for coordinating engine performance, hydraulic functions, and operator interface systems. When this fault activates, the machine may enter a protective derate mode to prevent potential damage from uncoordinated system operations.

The CAN bus system in Komatsu's Dash-8R series excavators operates on a dual-wire network that requires precise voltage levels and signal integrity. Any disruption compromises the machine's ability to function as an integrated system.

Common Symptoms

• Warning light illumination on the monitor panel, often accompanied by a communication error message or CAN system alert
• Intermittent loss of monitor display functions, including gauge readings, backup camera, or system status indicators
• Reduced engine power or hydraulic response as the machine enters protective derate mode
• Erratic behavior of electronic systems, such as automatic idle shutdown not functioning or climate control malfunctions
• Multiple fault codes appearing simultaneously across different systems due to communication breakdown

Potential Causes

The E10CA115 code in used PC850SE-8R excavators commonly stems from:

• Corroded or damaged CAN bus connectors, particularly at the main harness junction near the battery box or behind the operator cab—known wear points on this model
• Harness chafing or wire breaks in the engine compartment where the wiring harness routes near moving components or sharp edges
• Failed termination resistors at either end of the CAN network (typically 120-ohm resistors)
• ECM or controller module failure, though less common than harness issues in used machines
• Voltage irregularities from failing batteries, alternator issues, or poor ground connections affecting CAN bus power supply
• Water intrusion into connectors from damaged seals or improper maintenance

How to Troubleshoot and Fix Code E10CA115

Step 1: Visual Inspection Begin with a thorough inspection of all CAN bus harness connectors throughout the machine. Focus on the main engine harness, cab-to-chassis connectors, and any junction boxes. Look for corrosion (green/white deposits), bent pins, or moisture. On used excavators, pay special attention to harness routing near the swing bearing and hydraulic pump area where vibration causes wear.

Step 2: Electrical Testing Using a digital multimeter, check CAN bus voltage at the ECM connector. With ignition on, you should measure approximately 2.5V on both CAN-High and CAN-Low wires (relative to ground). Check termination resistance by disconnecting both ends of the network and measuring between CAN-High and CAN-Low—you should read approximately 60 ohms (two 120-ohm resistors in parallel).

Step 3: Diagnostic Software Analysis Connect Komatsu KOMTRAX or compatible diagnostic software to identify which specific controller is dropping communication. Monitor live data to see if the fault is intermittent or constant. Check for additional codes that may indicate the source controller.

Step 4: Harness Repair and Prevention If testing reveals harness damage, repair using proper CAN-rated twisted-pair wire and heat-shrink connections. Apply dielectric grease to all connectors during reassembly. For used machines, consider adding protective loom to vulnerable harness sections.

---

Disclaimer: This guide provides general diagnostic information. Complex electrical issues should be diagnosed by qualified technicians with access to manufacturer-specific tools and documentation. Always consult the official Komatsu service manual for your specific machine serial number.