Komatsu PC210-10 Fault Code DA2QKR: Technical Diagnosis and Repair Guide

What is Komatsu PC210-10 Fault Code DA2QKR?

Fault code DA2QKR on the Komatsu PC210-10 excavator indicates a communication error between the Machine Controller (MC) and the Engine Controller (ECM). This diagnostic trouble code specifically points to an interrupted or degraded CAN bus (Controller Area Network) data link that prevents proper information exchange between critical control systems.

This code triggers when the Machine Controller fails to receive valid data packets from the ECM within the programmed timeout period, typically 500 milliseconds. For the PC210-10's electronically-managed Komatsu SAA6D107E-1 engine, this communication failure is critical because the MC relies on real-time engine data to optimize hydraulic flow, implement auto-idle functions, and manage the integrated machine control system. Loss of this data link can result in degraded performance, fuel efficiency losses, and potential safety concerns.

Common Symptoms

When code DA2QKR is active, operators typically experience:

• Amber or red warning indicator illuminated on the monitor panel with "Communication Error" displayed
• Loss of auto-idle functionality – engine remains at high idle regardless of joystick position
• Disabled or erratic machine monitoring data – temperature, pressure, and fuel consumption readings become unavailable or freeze
• Potential engine derate in severe cases, limiting maximum RPM to protect the powertrain
• Intermittent loss of hydraulic response calibration, causing jerky or inconsistent boom/bucket movements

Potential Causes

The most common technical failures causing DA2QKR on used PC210-10 excavators include:

• CAN bus wiring harness damage – particularly at flex points near the engine mount, cab riser, or counterweight where vibration causes wire chafing
• Corroded or moisture-contaminated connectors at the MC (located under operator seat) or ECM (mounted on engine left side)
• Failed termination resistors in the CAN network (120-ohm resistors at network endpoints)
• ECM or MC internal failure – less common but possible in high-hour machines (8,000+ hours)
• Voltage supply issues – intermittent power to either controller caused by loose battery terminals, failing main relay, or damaged power distribution harness

How to Troubleshoot and Fix Code DA2QKR

Step 1: Perform Visual Inspection Begin by examining the CAN bus harness (twisted yellow/green wire pair) from the MC connector under the operator's seat to the ECM. Check for visible damage, particularly where the harness passes through the cab mount and engine bay bulkhead. On used excavators, inspect for oil contamination, rodent damage, or evidence of previous repairs with non-spec wire.

Step 2: Test CAN Bus Integrity Using a digital multimeter, disconnect both the MC and ECM connectors. Measure resistance between CAN-High and CAN-Low terminals at the MC connector – you should read approximately 60 ohms (two 120-ohm termination resistors in parallel). A reading above 100 ohms indicates an open circuit; below 40 ohms suggests a short circuit. Test continuity of each wire individually to identify the fault location.

Step 3: Verify Power Supply and Grounds With ignition on, verify the MC and ECM both receive stable 24V DC supply voltage. Check ground connections at both controllers using voltage drop testing – readings exceeding 0.2V indicate poor ground integrity, common in older machines with corroded chassis ground points.

Step 4: Clean and Reseat Connectors Disconnect the MC connector (C205) and ECM main connector. Spray with electrical contact cleaner and inspect pins for corrosion (green/white deposits). Pay special attention to the twisted-pair CAN wires – terminals often develop micro-corrosion in high-vibration environments. Apply dielectric grease before reconnection.

Step 5: Software Diagnostics Connect Komatsu KOMTRAX or compatible diagnostic software. Monitor live CAN bus traffic and verify message transmission rates. The ECM should broadcast engine data at approximately 100ms intervals. If hardware tests pass but communication remains absent, the issue may be internal controller failure requiring replacement.

Critical Note for Used Equipment: Before replacing expensive controllers ($1,200-2,800 each), thoroughly investigate harness wear points specific to the PC210-10. The main harness routing behind the hydraulic tank is notorious for developing shorts due to inadequate strain relief in early production units.

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Disclaimer: This guide provides general diagnostic procedures for experienced technicians. Always consult the official Komatsu PC210-10 Shop Manual and use proper lockout/tagout procedures. Incorrect diagnosis may result in unnecessary parts replacement or equipment damage. When in doubt, consult a Komatsu-certified technician with access to proprietary diagnostic equipment.