Komatsu PC210-8M0 Fault Code CA428: Complete Diagnostic Guide

What is Komatsu PC210-8M0 Fault Code CA428?

Fault Code CA428 indicates a communication error between the Controller Area Network (CAN) and the machine monitoring system, specifically a timeout or loss of message transmission from the engine controller (ECM) to the machine controller.

This code is triggered when the machine controller fails to receive expected CAN bus messages from the engine ECM within the specified time interval. On the PC210-8M0, this communication failure disrupts critical data exchange between controllers, affecting engine performance monitoring, hydraulic system coordination, and operator display functions. The CAN bus serves as the nervous system of modern excavators, making this fault particularly serious for operational reliability.

Common Symptoms

• Warning lights illuminated on the instrument panel, often accompanied by error messages on the monitor display
• Reduced engine power or unexpected engine derate, limiting machine productivity
• Intermittent loss of gauge readings including coolant temperature, engine RPM, or fuel level
• Hydraulic system response irregularities due to improper communication between engine load and hydraulic demand
• Machine may enter limp mode or experience difficulty starting in severe cases

Potential Causes

The CA428 code on used PC210-8M0 excavators typically stems from these technical issues:

• CAN bus wiring damage at known friction points, particularly where harnesses route near the swing bearing or through the cab firewall
• Corroded or loose CAN bus connectors on the ECM or machine controller, common in machines with high operating hours in wet or dusty conditions
• Failing engine ECM with degraded internal communication circuits, especially in machines exceeding 8,000 hours
• Termination resistor failure at either end of the CAN network (120-ohm resistors)
• Voltage supply issues to either controller caused by battery/charging system problems or corroded ground connections

How to Troubleshoot and Fix Code CA428

Step 1: Initial Inspection Start by visually inspecting all CAN bus harness routing from the engine ECM to the machine controller. Look for abraded insulation, pinched wires, or connector corrosion. On used excavators, pay special attention to harness sections near moving components. Check battery voltage—CAN communication requires stable 24V supply (11.5-14.5V per battery).

Step 2: Connector and Resistance Testing Disconnect CAN-H and CAN-L wires at both the ECM and machine controller. Using a digital multimeter, measure resistance between CAN-H and CAN-L terminals with all controllers disconnected. You should read approximately 60 ohms (two 120-ohm termination resistors in parallel). Readings significantly higher suggest open circuits or failed terminators.

Step 3: Active Communication Testing Reconnect all components and use Komatsu KOMTRAX or diagnostic software to monitor CAN bus activity in real-time. Check for intermittent dropouts while wiggling harnesses. If communication restores temporarily, focus on that harness section. Test termination resistors individually by accessing them at each controller—replace any measuring outside 115-125 ohms.

Step 4: Controller Evaluation If wiring checks pass, suspect ECM or machine controller failure. Swap controllers with known-good units if available, or consult dealer-level diagnostics to read deeper fault memory and CAN error counters.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific serial number and consider professional assessment for complex electrical issues or controller replacement.