What is Komatsu PC210LC-8M0 Fault Code DHA4KA?

Fault Code DHA4KA on the Komatsu PC210LC-8M0 indicates a communication error between the machine's Engine Controller (ECM) and the Machine Controller (PMC - Pump Controller), specifically related to a CAN (Controller Area Network) bus communication failure or data transmission timeout.

This diagnostic trouble code (DTC) signifies that critical operational data is not being properly exchanged between the engine management system and the hydraulic pump control system. The CAN bus serves as the digital nervous system for modern excavators, allowing multiple controllers to share real-time information about engine load, hydraulic demand, and operational modes. When this communication breaks down on the PC210LC-8M0, the machine cannot properly coordinate engine output with hydraulic performance, potentially leading to reduced efficiency, unexpected derating, or complete operational shutdown to prevent component damage.

Common Symptoms

When fault code DHA4KA is active, operators typically experience:

• Warning lamp illumination on the monitor panel, often accompanied by an audible alarm
• Reduced hydraulic power or sluggish implement response, as the controllers default to safe-mode operation
• Intermittent engine derating where RPM is limited to protect the powertrain during communication loss
• Error messages on the LCD display indicating controller communication issues
• Erratic fuel consumption patterns due to improper load-matching between engine and hydraulics

Potential Causes

The DHA4KA code in used PC210LC-8M0 excavators commonly stems from:

• Corroded or loose CAN bus connectors at the ECM or PMC connection points (particularly the 38-pin and 24-pin harness connectors)
• Damaged CAN bus wiring due to harness chafing near the engine mount points or along the right-side frame rail where vibration and heat exposure are highest
• Failed termination resistors within the CAN network (120-ohm resistors that maintain signal integrity)
• ECM or PMC internal failure, more common in machines with over 8,000 operating hours
• Voltage supply issues to either controller, often caused by failing main relays or poor grounding at G201 ground point

How to Troubleshoot and Fix Code DHA4KA

Step 1: Initial Inspection Begin by visually inspecting all CAN bus harness connections between the Engine Controller (located behind the operator cab) and Pump Controller (mounted on the hydraulic pump). Look specifically for green corrosion, bent pins, or moisture intrusion in connectors C1, C2 on the ECM and P1 on the PMC. On used excavators, check for harness wear where cables pass through rubber grommets near the swing bearing.

Step 2: Electrical Testing Using a digital multimeter, measure CAN-High and CAN-Low voltages at the ECM connector with the key in the ON position (engine off). You should read approximately 2.5V on each line at rest. Next, check termination resistance by disconnecting both controllers and measuring resistance between CAN-High and CAN-Low pins—you should read approximately 60 ohms (two 120-ohm resistors in parallel). Readings outside 55-65 ohms indicate termination failure.

Step 3: Advanced Diagnostics Connect Komatsu KOMTRAX or KTEC diagnostic software to monitor real-time CAN bus traffic. Look for intermittent dropouts or error frames. If software shows intermittent communication, perform a wiggle test on harnesses while monitoring to identify mechanical connection issues. For used machines, pay special attention to the harness routing near the engine-mounted fuel cooler, a known friction point on the PC210LC-8M0.

Step 4: Component Replacement If testing confirms faulty wiring, replace the affected CAN bus harness section (part number 20Y-06-31614 for main harness). When replacing connectors, apply dielectric grease to prevent future corrosion. If controllers are suspect, substitute with known-good units before purchasing replacements, as ECM (part 600-468-1200) and PMC units exceed $2,000 each.

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Disclaimer: This guide provides general diagnostic procedures for the Komatsu PC210LC-8M0. Always consult the official Komatsu service manual for your specific machine serial number. Complex electrical diagnostics should be performed by certified Komatsu technicians with appropriate diagnostic equipment. Improper repairs may cause additional system damage or safety hazards.