What is Doosan DX380-9C Fault Code E000655-10?

Fault Code E000655-10 indicates a communication error or abnormal signal from the Engine Control Module (ECM) to the Main Control Unit (MCU) on the Doosan DX380-9C excavator. This diagnostic trouble code specifically points to a disruption in the Controller Area Network (CAN) communication bus between these two critical control systems.

The ECM manages engine performance parameters including fuel injection timing, turbocharger boost pressure, and emissions controls, while the MCU oversees hydraulic functions and operator interface systems. When these controllers cannot communicate properly, the excavator's integrated systems cannot coordinate effectively, leading to reduced performance or complete operational shutdown. On the DX380-9C platform, this code is particularly critical because the machine relies on constant data exchange between controllers to optimize fuel efficiency and hydraulic response times during demanding digging and lifting operations.

Common Symptoms

• Warning lights: Engine malfunction lamp and main system error indicator illuminated simultaneously on the instrument cluster
• Reduced engine power: Engine automatically derates to low-idle or mid-range RPM, preventing full throttle operation
• Hydraulic system limitations: Sluggish or unresponsive hydraulic functions, particularly boom and bucket movements
• Intermittent shutdowns: Engine may stall unexpectedly during operation or fail to restart immediately
• Display errors: Monitor screen shows communication error messages or freezes during startup sequence

Potential Causes

The most common technical failures triggering E000655-10 on used DX380-9C excavators include:

• CAN bus wiring damage: Harness chafing along the main chassis rail near the fuel tank mounting bracket—a known wear point on this model
• Corroded connectors: Moisture intrusion in the 38-pin ECM connector (C101) or 24-pin MCU connector (C205), especially on machines operating in wet environments
• Faulty termination resistors: 120-ohm CAN termination resistors failing at either end of the communication network
• ECM or MCU internal failure: Controller circuit board damage from voltage spikes or age-related component degradation
• Ground connection issues: Loose or corroded ground strap between engine block and chassis frame (G102 ground point)

How to Troubleshoot and Fix Code E000655-10

Step 1: Visual Inspection Begin by examining the CAN bus harness routing from the ECM (located on the right side of the engine) to the MCU (mounted behind the operator cab). Look for abraded wire insulation, particularly where the harness passes through bulkhead grommets. On used excavators, check for previous repair attempts using non-OEM wire splices or electrical tape that may have degraded.

Step 2: Connector and Ground Testing Disconnect connectors C101 and C205 and inspect pins for corrosion or bent terminals. Clean with electrical contact cleaner and verify pin tension. Using a digital multimeter, check continuity of the ground strap at G102—resistance should be less than 0.5 ohms to chassis. Inspect for green corrosion buildup on ground terminals.

Step 3: CAN Bus Electrical Testing With ignition on and engine off, measure voltage between CAN-High (typically yellow wire) and CAN-Low (typically green wire) at the ECM connector. You should read approximately 2.5V differential voltage. Using a multimeter set to resistance mode, verify termination resistance across CAN-High and CAN-Low reads between 55-65 ohms (indicating both 120-ohm resistors are present). Readings outside this range indicate termination failure.

Step 4: Advanced Diagnostics Connect Doosan DMS-5 diagnostic software or compatible scan tool to the service port. Monitor live CAN bus traffic and check for message dropouts or error frame counts exceeding 5%. For used equipment, perform a controller voltage supply test—ECM and MCU should receive stable 24V DC with less than 0.3V ripple during cranking.

Step 5: Component Replacement Protocol If wiring and connections test good, suspect controller failure. Before replacing expensive modules on used machines, verify the power supply relay (K14) and associated fuses F8 and F12 in the main fuse box. Replace components individually, starting with the most accessible and least expensive options.

---

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Doosan service manual for your specific machine serial number range. Improper diagnostics on high-voltage electrical systems can cause equipment damage or personal injury. When working with used excavators of unknown maintenance history, professional diagnostic services are recommended to avoid misdiagnosis and unnecessary parts replacement.