Komatsu PC220-10 Fault Code DA2QKR: Complete Diagnostic Guide

What is Komatsu PC220-10 Fault Code DA2QKR?

Fault Code DA2QKR indicates a communication error between the machine's Main Controller (PMC - Pump Control Module) and the Engine Controller (ECM) on the Komatsu PC220-10 excavator. This diagnostic trouble code specifically points to a CAN bus communication failure or data transmission interruption within the machine's integrated control network.

This code is critical for the PC220-10's performance because the PMC and ECM must constantly exchange data to optimize hydraulic pump output, engine speed, and fuel efficiency. When communication breaks down, the machine's CLSS (Closed-Center Load Sensing System) cannot properly match hydraulic demand with engine power, resulting in reduced performance and potential safety concerns during operation.

Common Symptoms

When fault code DA2QKR is active, operators typically experience:

• Check Engine light or Action lamp illuminated on the monitor panel
• Noticeable loss of hydraulic power or sluggish boom/arm movement
• Engine running at fixed RPM regardless of throttle input (limp mode)
• Error messages on the multi-information display indicating controller communication failure
• Intermittent power loss that may temporarily resolve after restarting the machine

Potential Causes

The most common technical reasons for DA2QKR appearing on used PC220-10 excavators include:

• CAN bus wiring harness damage - particularly at known rub points near the battery box or along the right-side frame rail where harnesses pass through grommets
• Corroded or loose connector pins on the 38-pin ECM connector (C1) or PMC connector (C2)
• Failed terminating resistor within the CAN network (120-ohm resistance degradation)
• ECM or PMC internal failure - more common in high-hour machines (8,000+ hours)
• Voltage irregularities from failing alternator or poor battery ground connections
• Water intrusion into controller housings from compromised seals or damaged wiring boots

How to Troubleshoot and Fix Code DA2QKR

Step 1: Visual Inspection Begin by thoroughly inspecting all wiring harnesses between the engine ECM (located left side of engine) and pump controller (mounted on main pump). Look specifically for frayed wires, damaged insulation, or evidence of harness rubbing against frame components. On used excavators, pay special attention to connector boots for cracks or moisture intrusion.

Step 2: Connector and Voltage Checks Disconnect the 38-pin ECM connector and PMC connector. Inspect pins for corrosion, bent contacts, or pushed-back terminals. Using a digital multimeter, verify proper supply voltage at the ECM (Pin 1: should read 24V with key on). Check chassis ground integrity at ECM mounting bolts (resistance should be less than 1 ohm to battery negative).

Step 3: CAN Bus Resistance Test With controllers disconnected and ignition off, measure resistance between CAN-H and CAN-L terminals at the ECM connector. You should read approximately 60 ohms (indicating two 120-ohm terminating resistors in parallel). A reading significantly higher suggests an open circuit; lower readings may indicate a short in the CAN bus network.

Step 4: Diagnostic Software Analysis Connect Komatsu KOMTRAX diagnostic software or an aftermarket tool compatible with the PC220-10's system. Monitor live data streams to determine if the ECM and PMC are transmitting data. Check for additional stored codes that might indicate which controller initiated the communication fault.

Step 5: Component Replacement If wiring and connections test satisfactory, the fault likely resides within a controller. For used machines, ECM failures are more common than PMC issues. Consider sourcing a remanufactured or tested-used controller rather than new OEM parts to reduce costs. Always ensure replacement controllers are programmed with correct machine parameters before installation.

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Disclaimer: This guide provides general troubleshooting information for experienced diesel mechanics. Always consult the official Komatsu service manual for your specific machine serial number, and consider professional diagnostic services for complex electrical issues. Improper repairs may result in further damage or safety hazards.