Komatsu PC750LC-7 Fault Code DA2SKA: Complete Diagnostic Guide

What is Komatsu PC750LC-7 Fault Code DA2SKA?

Fault Code DA2SKA indicates a communication error or data link failure between the engine controller (ECM) and the machine's main monitor system on the Komatsu PC750LC-7 excavator. This code specifically relates to the CAN bus communication network that allows critical systems to exchange operational data in real-time.

The DA2SKA code typically signals that the electronic control module (ECM) cannot properly transmit or receive data packets through the machine's internal network. For the PC750LC-7, this communication breakdown is critical because it prevents the operator from receiving essential engine parameters, hydraulic system feedback, and diagnostic information necessary for safe and efficient operation.

Common Symptoms

When fault code DA2SKA is active, operators typically experience:

• Monitor display failures showing blank screens, frozen readings, or intermittent gauge operation
• Warning lights illuminating on the dashboard without corresponding fault descriptions
• Loss of real-time data including engine RPM, hydraulic oil temperature, and fuel level readings
• Inability to access diagnostic menus through the standard operator interface
• Intermittent engine derating or performance limitations as a protective measure

Potential Causes

The most common technical causes for DA2SKA on used PC750LC-7 excavators include:

• Corroded or damaged CAN bus connectors at the ECM or monitor harness junction points
• Wiring harness chafing near the engine bay or cab mounting points where vibration causes insulation wear
• Failed termination resistors within the CAN network circuit (typically 120-ohm resistors)
• ECM internal communication module failure due to age, moisture intrusion, or voltage spikes
• Loose or oxidized ground connections affecting the entire communication network
• Monitor unit malfunction preventing proper data reception and display

How to Troubleshoot and Fix Code DA2SKA

Step 1: Visual Inspection Begin by inspecting all wiring harnesses between the ECM (located near the engine) and the main monitor. On used excavators, check for harness rub points near the cab pivot, engine mounts, and through bulkhead connectors. Look for abraded insulation, pinched wires, or evidence of rodent damage.

Step 2: Connector Examination Disconnect and inspect the CAN bus connectors at both the ECM and monitor ends. Clean any corrosion using electrical contact cleaner and verify pin integrity. Check for bent pins or moisture intrusion—common issues on machines with 5,000+ operating hours.

Step 3: Resistance Testing Using a digital multimeter, measure resistance across the CAN-High and CAN-Low wires with all devices disconnected. You should read approximately 60 ohms (two 120-ohm termination resistors in parallel). Readings significantly higher suggest open circuits or failed terminators.

Step 4: Voltage Verification With the key on and engine off, measure CAN bus voltage at the ECM connector. Expect approximately 2.5V on both CAN-High and CAN-Low lines at rest. Significant deviation indicates network problems or short circuits.

Step 5: Diagnostic Software Analysis Connect Komatsu KOMTRAX or compatible diagnostic software to read detailed communication logs and identify which specific node is failing to respond.

Disclaimer: This guide provides general troubleshooting procedures. Complex electrical diagnostics on heavy equipment should be performed by qualified technicians with proper training and equipment. Always consult the official Komatsu service manual for your specific machine serial number.