What is Doosan DX215-9C Fault Code E520711-12 (P108E)?

Fault Code E520711-12 (P108E) on the Doosan DX215-9C excavator indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to a CAN (Controller Area Network) bus communication error between the engine ECM and the main machine controller. This code signals that critical data transmission between the engine management system and the excavator's primary control systems has been interrupted or degraded.

This fault is critical because the DX215-9C relies on continuous communication between its Doosan DL08 engine ECM and the machine controller to optimize hydraulic performance, monitor emissions systems, and regulate power delivery. When communication fails, the machine may enter a protective derate mode or experience erratic behavior that compromises jobsite productivity.

Common Symptoms

• Engine derate or power limitation – the excavator may operate at reduced RPM or restrict hydraulic flow
• Multiple warning lights illuminated on the dashboard simultaneously, including engine and system malfunction indicators
• Intermittent loss of display information on the monitor panel, with missing engine parameters or system data
• Erratic hydraulic response or inconsistent swing/boom speed due to incomplete communication between controllers
• Engine may fail to start or experience unexpected shutdowns during operation

Potential Causes

The most common technical causes for Code E520711-12 on used DX215-9C excavators include:

• CAN bus wiring harness damage – particularly at flex points near the engine firewall or along the main chassis harness where vibration causes wire chafing
• Corroded or loose connector pins at the ECM or main controller connection points, especially on machines with high hour counts or exposure to moisture
• Failed terminating resistor on the CAN network (120-ohm resistor failure disrupts signal integrity)
• ECM or machine controller internal failure – circuit board degradation in older units
• Voltage supply issues to either controller caused by failing relays, poor grounds, or battery connection problems
• Aftermarket component interference – non-OEM attachments or modifications that introduce electrical noise

How to Troubleshoot and Fix Code E520711-12 (P108E)

Step 1: Visual Inspection of Harness and Connectors Inspect the main wiring harness between the engine ECM (located on the right side of the engine) and the machine controller (in the cab area). Look for obvious damage, chafing at metal edges, or burnt wire insulation. Check all CAN bus connectors for corrosion, bent pins, or moisture intrusion – these are common failure points on used excavators operating in harsh environments.

Step 2: Verify CAN Bus Integrity Using a digital multimeter, measure the resistance between the CAN High and CAN Low terminals at the ECM connector with the key off and all controllers disconnected. You should read approximately 60 ohms (two 120-ohm terminating resistors in parallel). If you read infinite resistance, a terminating resistor has failed or there's an open circuit in the network.

Step 3: Check Power Supply and Grounds Verify that both the engine ECM and machine controller are receiving proper voltage (typically 24V DC on this model). Check for voltage drop across ground connections – clean and tighten all ground points on the engine block and frame. Poor grounds are particularly common on high-hour used machines.

Step 4: Use Doosan Diagnostic Software Connect Doosan DMS (Diagnostic Master System) or compatible diagnostic software to the service port. Monitor live CAN bus traffic and check for specific sub-codes that identify which controller is failing to communicate. This software can also perform active tests to isolate the faulty component.

Step 5: Replace Faulty Components If diagnostics point to a specific failed component (ECM, controller, or harness section), replace only after confirming the diagnosis. For used excavators, consider sourcing OEM Doosan parts rather than aftermarket alternatives, as CAN communication systems are sensitive to component specifications.

Disclaimer: This guide provides general diagnostic information. Complex electrical issues should be diagnosed by qualified technicians with proper Doosan diagnostic equipment. Always consult the official service manual and follow safety protocols when working on heavy equipment.