What is Komatsu PC110-8M0 Fault Code DAZQKR?

Fault Code DAZQKR on the Komatsu PC110-8M0 indicates a communication error between the Engine Control Module (ECM) and the Machine Control Module (MCM), specifically related to CAN bus data transmission failure. This code is triggered when the main controller cannot receive or properly interpret signals from the engine management system, disrupting the coordinated operation between hydraulic functions and engine performance.

This fault is critical for the PC110-8M0 because this model relies on integrated electronic communication to regulate engine load, hydraulic pump flow, and fuel injection timing. When the CAN bus communication fails, the excavator cannot optimize power distribution, leading to reduced operational efficiency and potential component protection shutdowns. For used excavators, this code often emerges as wiring harnesses age and connector integrity deteriorates.

Common Symptoms

• Intermittent or complete loss of hydraulic power, particularly under heavy load conditions
• Engine fails to respond properly to throttle inputs or operates in fixed RPM mode
• Multiple warning lights illuminating simultaneously on the instrument cluster, including engine and hydraulic system alerts
• Machine enters derate mode or limp-home operation, limiting travel speed and hydraulic flow
• Erratic gauge readings showing inconsistent engine temperature, fuel level, or hydraulic pressure data

Potential Causes

The most common causes for DAZQKR on used Komatsu PC110-8M0 excavators include:

• Damaged or corroded CAN bus wiring harness, especially at known rub points near the swing bearing and along the boom base where cables flex repeatedly
• Loose or oxidized connectors at the ECM or MCM, particularly the 38-pin main harness connector which is vulnerable to moisture intrusion
• Failed termination resistor on the CAN bus network (120-ohm resistor failure disrupts signal integrity)
• ECM or MCM internal failure, more common in machines with 8,000+ operating hours
• Voltage irregularities from failing alternator or battery connections causing communication dropouts
• Aftermarket modifications or repairs that compromised factory wiring or grounding points

How to Troubleshoot and Fix Code DAZQKR

Step 1: Visual Inspection and Connector Check Begin by inspecting all wiring harnesses between the ECM (located behind the operator cab) and MCM (typically mounted near the hydraulic pump). Look specifically for harness chafing at the swing post area and boom pivot points—common failure locations on used PC110 models. Clean and inspect the 38-pin connector at both modules, checking for green corrosion, bent pins, or moisture. Apply dielectric grease after cleaning.

Step 2: CAN Bus Continuity and Resistance Testing Using a digital multimeter, disconnect both the ECM and MCM connectors. Measure resistance between CAN-High and CAN-Low pins (refer to Komatsu service manual for specific pin locations). You should read approximately 60 ohms with both modules disconnected, indicating proper termination resistors. Check continuity of each CAN wire individually—any reading above 2 ohms suggests damaged wiring requiring replacement.

Step 3: Voltage Supply Verification With the ignition on but engine off, verify that both the ECM and MCM receive proper supply voltage (typically 24V on this model). Check ground connections at both modules—on used excavators, ground points often corrode, creating intermittent faults. Measure voltage drop; anything above 0.2V indicates poor grounding requiring cleaning or relocation.

Step 4: Diagnostic Software Scan Connect Komatsu KOMTRAX or compatible diagnostic software to read real-time CAN bus traffic. Monitor communication packets while wiggling harnesses to identify intermittent failures. If communication drops when manipulating specific areas, targeted harness replacement is needed rather than complete rewiring.

Step 5: Component Replacement Priority For used machines, replace components in this cost-effective order: connectors and terminals first, then wiring harness sections, followed by termination resistors, and finally control modules only if all else fails. Many DAZQKR codes resolve with simple connector maintenance rather than expensive module replacement.

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Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu service manual for your specific machine serial number. If you're uncomfortable performing electrical diagnostics, contact a certified Komatsu technician to prevent further damage to electronic systems.