What is Komatsu PC110-8M0 Fault Code DA2QKR?

Fault Code DA2QKR on the Komatsu PC110-8M0 excavator indicates a communication error between the engine ECM (Engine Control Module) and the machine's main controller or monitor panel. This diagnostic trouble code specifically points to a disruption in the CAN bus communication network that allows critical machine systems to exchange data.

In the PC110-8M0 model, this code typically signals that the engine controller cannot properly transmit or receive operational data to the monitor system, affecting real-time diagnostics and performance management. This is critical because the CAN bus network controls coordination between engine parameters, hydraulic systems, and operator interface displays. When communication fails, the machine may enter a protective derate mode to prevent potential damage from unmonitored operating conditions.

Common Symptoms

When fault code DA2QKR is active on your Komatsu PC110-8M0, operators typically experience:

• Warning lights illuminated on the instrument cluster, particularly the engine or system malfunction indicator
• Intermittent or complete loss of gauge readings (fuel level, coolant temperature, hour meter)
• Engine power reduction or automatic derate limiting machine performance to protect components
• Error messages displayed on the monitor screen indicating communication failure
• Erratic instrument behavior where displays flicker, freeze, or show incorrect readings

Potential Causes

The most common technical reasons for DA2QKR appearing on used PC110-8M0 excavators include:

• Damaged CAN bus wiring harness between the ECM and monitor, often caused by rubbing against the engine block or frame rails during years of vibration
• Corroded or loose connectors at the ECM harness plug or monitor panel connections—particularly common in machines with high humidity exposure
• Failing ECM or monitor controller due to age-related component degradation or moisture intrusion
• Voltage supply issues to either the ECM or monitor caused by battery problems, poor grounding points, or alternator irregularities
• Software corruption in the ECM or monitor requiring reprogramming, especially after previous electrical work or jumpstarting incidents

How to Troubleshoot and Fix Code DA2QKR

Step 1: Visual Harness Inspection Begin by thoroughly inspecting the main wiring harness running from the engine ECM (located on the right side of the engine) to the cab monitor panel. Look for obvious damage, abrasion points where wires contact metal surfaces, or areas where protective loom has deteriorated. On used excavators, pay special attention to harness routing near the engine mounting points and swing bearing area where movement creates friction.

Step 2: Connector and Ground Verification Disconnect and inspect all CAN bus connectors at both the ECM and monitor ends. Clean connector pins with electrical contact cleaner and check for corrosion (green/white deposits), bent pins, or moisture intrusion. Verify the ground connections at both components using a multimeter—resistance to chassis ground should be less than 1 ohm. Used machines often develop poor grounds due to paint buildup or corrosion at mounting bolts.

Step 3: CAN Bus Continuity and Resistance Testing Using a digital multimeter, test continuity of the CAN-High and CAN-Low wires (typically yellow and green wires in Komatsu systems) between ECM and monitor. Measure termination resistance across the CAN-High and CAN-Low terminals—it should read approximately 60 ohms with both devices connected. Values significantly outside this range indicate open circuits, shorts, or internal device failures.

Step 4: Voltage Supply Check Verify that both the ECM and monitor are receiving proper supply voltage (typically 24V on this model). Check voltage at the power supply pins with the key in the ON position. Low voltage often indicates battery, alternator, or fusible link problems that prevent stable communication.

Step 5: Diagnostic Software Analysis Connect Komatsu KOMTRAX or compatible diagnostic software to access detailed fault memory and live data streams. This will confirm whether communication is completely absent or intermittent, and may reveal additional fault codes that pinpoint the exact component failure. For used excavators, check fault occurrence frequency—intermittent codes often indicate vibration-related connector issues rather than component failure.

Step 6: Component Replacement or Reprogramming If harness and connections test satisfactory, the issue likely resides in the ECM or monitor controller itself. Consider ECM reprogramming first using manufacturer software, as corrupted firmware occasionally causes communication errors. If reprogramming fails, replacement of the failing component becomes necessary—always source genuine Komatsu parts or verified remanufactured units to ensure CAN protocol compatibility.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu PC110-8M0 service manual and consider professional diagnostic assistance for complex electrical issues. Improper repairs may cause additional damage or safety hazards.