What is Komatsu PC210LC-10 Fault Code DAZQKR?

Fault code DAZQKR on the Komatsu PC210LC-10 excavator indicates a communication error between the engine controller (ECM) and the machine's main monitor or display unit. This diagnostic trouble code (DTC) specifically points to a disruption in the Controller Area Network (CAN) bus communication system that allows critical operational data to be transmitted between control modules.

This code is particularly critical for the PC210LC-10 because the CAN bus system controls the integration between the Komatsu SAA6D107E-1 engine's electronic controls and the machine's hydraulic management system. When communication fails, the excavator may enter a protective derate mode or display incorrect operational parameters, compromising both productivity and component protection protocols. On used machines, this fault often stems from age-related deterioration of electrical connections rather than actual controller failures.

Common Symptoms

When fault code DAZQKR is active on your PC210LC-10, operators typically experience:

• Monitor display failure or intermittent blackouts showing no engine parameters, fuel level, or hydraulic temperature readings
• Check engine light or master warning lamp illuminated on the dash panel
• Erratic gauge behavior with fluctuating readings for RPM, coolant temperature, or fuel levels
• Engine derate or limp mode activation, limiting machine performance to protect components
• Inability to access machine diagnostics through the standard monitor interface

Potential Causes

The most common technical causes for DAZQKR fault code on used PC210LC-10 excavators include:

• CAN bus wiring harness damage at known wear points behind the operator cab or near the engine bulkhead where harnesses route through metal panels
• Corroded or loose connector pins at the main monitor connection (often the 20-pin connector behind the display panel)
• Failed main monitor unit due to moisture infiltration or component aging (common in machines over 8,000 hours)
• ECM connector corrosion at the C1 or C2 harness connections, particularly on machines operated in marine or high-humidity environments
• Damaged terminating resistors on the CAN bus network at either the ECM or monitor ends
• Faulty ground connections at G101 or G102 grounding points specific to the PC210LC-10 chassis

How to Troubleshoot and Fix Code DAZQKR

Step 1: Visual Inspection of Harnesses and Connectors Begin with a thorough physical inspection of the main harness routing from the ECM (located right side of engine) to the monitor panel. On used PC210LC-10s, check specifically where the harness passes through the bulkhead near the hydraulic pump—this is a known rub point. Look for abraded insulation, pinched wires, or evidence of previous repairs. Disconnect and inspect all connectors for corrosion, bent pins, or moisture. Clean connections with electrical contact cleaner and apply dielectric grease.

Step 2: CAN Bus Continuity and Resistance Testing Using a digital multimeter (DMM), measure resistance between CAN-High and CAN-Low terminals at the ECM connector with all power off and connectors unplugged. You should read approximately 60 ohms if terminating resistors are intact. Check continuity of individual CAN wires from ECM to monitor—any reading above 2 ohms indicates excessive resistance from corrosion or broken strands. Verify terminating resistor presence (typically 120 ohms each) at network endpoints.

Step 3: Power Supply and Ground Circuit Verification With ignition on (engine off), verify the monitor receives proper battery voltage (typically 24V on PC210LC-10) at the power supply pin. Check ground circuit integrity by measuring voltage drop from monitor ground to battery negative—readings above 0.2V indicate poor grounding. Clean and tighten chassis ground points G101 and G102. For used excavators, remove ground bolts completely, wire-brush contact surfaces, and apply anti-corrosion compound before reinstallation.

Step 4: Component Isolation Testing If harness and power checks pass, use Komatsu KOMTRAX diagnostic software or compatible J1939 CAN scanner to monitor live communication. Disconnect the main monitor and observe if the ECM fault clears—this isolates whether the monitor or ECM is causing bus disruption. On older machines, the monitor LCD unit itself often develops internal shorts that corrupt bus communication. Swap with a known-good monitor unit if available before replacing the more expensive ECM.

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Disclaimer: This guide provides general troubleshooting procedures for experienced technicians working on used heavy equipment. Always consult the official Komatsu PC210LC-10 service manual and follow proper lockout/tagout safety procedures. If unfamiliar with CAN bus diagnostics or electrical systems, consult a certified Komatsu technician to prevent further damage to electronic components.