Komatsu PC110-8M0 Fault Code DXA8KA: Expert Diagnostic Guide

What is Komatsu PC110-8M0 Fault Code DXA8KA?

Fault Code DXA8KA indicates a communication error between the Engine Control Module (ECM) and the Machine Controller on the Komatsu PC110-8M0 excavator. This diagnostic trouble code (DTC) specifically points to a CAN bus communication failure or data transmission interruption within the machine's electronic network.

The PC110-8M0 utilizes a sophisticated Controller Area Network (CAN) system where the ECM and machine controller constantly exchange critical operational data. When this communication pathway fails, the machine cannot properly coordinate engine performance with hydraulic demands, potentially causing severe operational limitations. This code is particularly critical because it affects the integrated control system that manages fuel efficiency, emissions compliance, and hydraulic response timing.

Common Symptoms

When DXA8KA is active, operators typically experience:

• Engine warning lamp illuminated on the instrument cluster with possible simultaneous hydraulic system alerts
• Reduced engine power or automatic derate mode, limiting machine to 70-80% normal performance
• Erratic hydraulic response with delayed or inconsistent boom, arm, or bucket movements
• Intermittent dashboard gauge failures, including loss of engine temperature, fuel level, or hour meter readings
• Machine may enter limp mode upon startup, preventing normal operation until the ignition is cycled

Potential Causes

The most common technical failures triggering DXA8KA on used PC110-8M0 excavators include:

• CAN bus wiring harness damage at known rub points near the turntable bearing and along the right-side chassis rail
• Corroded or moisture-contaminated connectors at the ECM (located behind the operator seat) or machine controller junction
• Failed termination resistor on the CAN network (120-ohm resistor typically located at ECM or controller end)
• ECM or machine controller internal failure, more common in machines exceeding 6,000 operating hours
• Low battery voltage (below 22V on 24V systems) causing intermittent communication dropouts
• Aftermarket electrical accessories improperly tied into the CAN network creating signal interference

How to Troubleshoot and Fix Code DXA8KA

Step 1: Perform Visual Inspection Begin by thoroughly inspecting the CAN bus harness from the ECM to the machine controller. On used excavators, check the harness routing near the slew bearing where vibration and movement cause insulation wear. Look for chafed wires, exposed copper, or damaged protective loom. Inspect all connector pins for corrosion, bent terminals, or moisture intrusion.

Step 2: Verify Electrical Integrity Using a digital multimeter, measure battery voltage (should be 24-28V with engine running). Check CAN-High and CAN-Low wire resistance between ECM and controller—should read approximately 60 ohms with termination resistors intact. Disconnect both controllers and measure termination resistor continuity; each should read 120 ohms.

Step 3: Test Communication Signal If equipped with Komatsu KOMTRAX diagnostic software or compatible scan tool, monitor live CAN bus data transmission. Erratic voltage swings or complete signal loss confirm wiring issues. Wiggle suspect harness sections while monitoring; intermittent faults indicate internal wire breakage common in used machines.

Step 4: Address Common Failure Points Replace corroded connectors with dielectric grease application on reassembly. If harness damage is found at rub points, reroute and secure with proper vibration-resistant clamps. For machines with 5,000+ hours, consider preventive replacement of the main CAN harness as insulation degradation is common.

Professional Disclaimer: While these troubleshooting steps are based on field-proven diagnostic procedures, complex CAN network issues may require factory-level diagnostic equipment and trained technicians. Always consult Komatsu service documentation and consider professional assistance for ECM or controller replacement to ensure proper programming and calibration.