Komatsu PC200-8E0 Fault Code DA2RMC: Complete Diagnostic Guide

What is Komatsu PC200-8E0 Fault Code DA2RMC?

Fault code DA2RMC indicates a communication error between the Engine Controller (ECM) and the Hydraulic Pump Controller (PPC/PMC) on the Komatsu PC200-8E0 excavator. This code specifically points to a CAN (Controller Area Network) bus communication failure or data transmission irregularity between these critical control modules.

The ECM and Hydraulic Pump Controller must constantly exchange data to optimize engine performance and hydraulic flow rates. When this communication breaks down, the machine cannot properly match engine output to hydraulic demand, resulting in inefficient operation and potential power loss. On the PC200-8E0's electronically controlled hydraulic system, this communication is essential for the machine's sophisticated load-sensing capabilities and fuel efficiency features.

Common Symptoms

• Machine enters derate mode with noticeable power reduction, limiting swing speed and digging force
• Warning lamp illumination on the monitor panel, often accompanied by a buzzer alert
• Erratic hydraulic response, including inconsistent swing speeds or sluggish boom/arm movements
• Increased fuel consumption due to the system reverting to fail-safe mode with fixed pump displacement
• Intermittent performance issues where the machine operates normally, then suddenly loses power

Potential Causes

The DA2RMC code typically results from these specific failures common in used PC200-8E0 excavators:

• CAN bus wiring harness damage at known rub points near the fuel tank bracket and along the right-side main frame rail
• Corroded or loose connectors at the ECM (located behind the operator's seat) or Pump Controller (mounted on the hydraulic pump)
• Water intrusion into control module connectors, especially on machines stored outdoors without proper cab sealing
• Failed termination resistors on the CAN bus network (120-ohm resistors at network endpoints)
• ECM or Pump Controller internal failure, more common in high-hour machines (8,000+ hours)
• Low battery voltage or poor grounding causing intermittent communication dropouts

How to Troubleshoot and Fix Code DA2RMC

Step 1: Visual Inspection Begin by inspecting the wiring harness between the ECM and Pump Controller. On used excavators, check for wire chafing where the harness passes through the frame opening near the hydraulic tank. Examine all connectors for corrosion, bent pins, or moisture—clean with electrical contact cleaner and apply dielectric grease.

Step 2: CAN Bus Voltage Testing Using a multimeter, check CAN-High and CAN-Low voltage at the ECM connector with the key on, engine off. You should read approximately 2.5V on CAN-High and 2.5V on CAN-Low (both relative to ground). Measure resistance between CAN-High and CAN-Low terminals—it should read approximately 60 ohms (indicating proper termination resistors).

Step 3: Connector and Ground Verification Disconnect both the ECM and Pump Controller connectors. Inspect for corrosion or pushed-back pins (common in used machines). Verify ground circuits using a multimeter—resistance to chassis ground should be less than 1 ohm. Check battery voltage (should be 12.4V+ with engine off).

Step 4: Component Replacement If wiring and connections test properly, connect Komatsu KOMTRAX diagnostic software or an authorized diagnostic tool to read real-time communication data. If one controller shows no communication, replacement may be necessary. On used excavators with 6,000+ hours, consider replacing both controllers if one has failed, as they often age similarly.

Critical for Used Machines: Before replacing expensive controllers, thoroughly inspect the harness routing. PC200-8E0 excavators commonly experience wire fatigue where the harness flexes near the swing bearing. Replace worn grommets and secure loose wiring.

---

Disclaimer: This guide provides general troubleshooting information. Complex electrical diagnostics should be performed by qualified Komatsu technicians with proper diagnostic equipment. Always consult the official Komatsu service manual for your specific machine serial number before performing repairs.