Komatsu PC1250-11R Fault Code DA2LKA: Complete Diagnostic Guide

What is Komatsu PC1250-11R Fault Code DA2LKA?

Fault Code DA2LKA indicates a communication error between the Engine Control Module (ECM) and the Machine Control Module (MCM) on the Komatsu PC1250-11R excavator. This code specifically signals that the CAN bus communication network has detected an abnormal data transmission or complete loss of signal between these critical control systems.

The PC1250-11R relies on continuous data exchange between the ECM (managing engine performance) and MCM (controlling hydraulic and machine functions) to optimize fuel efficiency, power delivery, and operational safety. When this communication fails, the machine cannot properly coordinate engine output with hydraulic demand, potentially causing severe performance degradation or complete shutdown.

Common Symptoms

When DA2LKA is active, operators typically experience:

• Engine derate mode or automatic power reduction to protect systems
• Illuminated warning lights on the monitor panel, specifically communication-related alerts
• Erratic hydraulic response or sluggish boom/bucket movements due to ECM-MCM coordination failure
• Intermittent engine stalling or rough idle conditions
• Monitor display errors showing incomplete or frozen machine data

Potential Causes

The most common technical failures triggering DA2LKA on used PC1250-11R excavators include:

• CAN bus wiring harness damage – particularly at flex points near the engine mount or cab pivot where vibration causes wire chafing
• Corroded or loose connector pins on the ECM or MCM communication harnesses (common in machines with 5,000+ hours)
• Failed termination resistor on the CAN network (120-ohm resistor degradation)
• ECM or MCM internal failure – less common but possible in high-hour machines
• Voltage supply issues to either control module (low battery voltage or poor grounding)
• Water intrusion into harness connectors, especially on machines stored outdoors

How to Troubleshoot and Fix Code DA2LKA

Step 1: Visual Inspection Begin with a thorough physical examination of all wiring harnesses between the ECM and MCM. On used excavators, focus on areas where harnesses route near moving components or sharp edges. Check for abraded insulation, pinched wires, or oil contamination that degrades insulation.

Step 2: Connector and Termination Check Disconnect the CAN bus connectors at both the ECM and MCM. Inspect pins for corrosion, bent contacts, or moisture. Using a digital multimeter, verify the termination resistance across CAN-High and CAN-Low wires—you should read approximately 60 ohms with both modules connected (two 120-ohm resistors in parallel).

Step 3: Voltage and Communication Testing With the key on, measure voltage supply to both modules (should be 24V nominal). Use Komatsu KOMTRAX diagnostic software or compatible scan tool to monitor live CAN bus traffic. If one module shows no communication, isolate it by disconnecting and retesting—this identifies whether the ECM or MCM is the faulty component.

Step 4: Harness Continuity Test With modules disconnected, test continuity and resistance on CAN-High and CAN-Low wires between ECM and MCM connectors. Any reading above 5 ohms indicates excessive resistance from damaged conductors or poor crimps.

For used excavators, replacing entire harness sections is often more reliable than splicing repairs, as hidden internal wire damage frequently exists beyond visible wear points.

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Disclaimer: This guide provides general diagnostic procedures. Always consult the official Komatsu service manual for your specific machine serial number and consider professional assistance for complex electrical diagnostics.