What is Doosan DX215-9C Fault Code E000735-06 (P0265)?

Fault Code E000735-06 (P0265) indicates a malfunction in the Cylinder #2 Injector Circuit on the Doosan DX215-9C excavator. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects an abnormal electrical signal—typically a short circuit, open circuit, or resistance value outside specified parameters—in the wiring or solenoid controlling the number two fuel injector.

This code is critical for the DX215-9C's performance because the common rail fuel injection system relies on precise electronic control of each injector solenoid. When Cylinder #2 cannot deliver fuel properly, the engine experiences power loss, rough running, and increased emissions. The ECM may activate derate mode to protect the engine from further damage, significantly reducing machine productivity on the jobsite.

Common Symptoms

• Check Engine Light or malfunction indicator lamp illuminated on the instrument cluster
• Noticeable engine misfiring or rough idle, particularly when under load
• Reduced engine power and sluggish hydraulic response during digging or lifting operations
• Black or white smoke from the exhaust stack, indicating incomplete combustion
• Possible fuel consumption increase due to compensating fuel delivery to other cylinders

Potential Causes

The most common technical causes for this fault code on used DX215-9C excavators include:

• Faulty injector solenoid on Cylinder #2 due to coil winding deterioration or internal short
• Damaged wiring harness between the ECM and injector, especially at known rub points near the engine valve cover or fuel rail mounting brackets
• Corroded or loose electrical connectors at the injector plug—common in machines exposed to moisture or harsh environments
• ECM internal driver circuit failure affecting only the #2 cylinder output channel
• Intermittent short to ground caused by chafed insulation where harnesses contact metal brackets or engine components

How to Troubleshoot and Fix Code E000735-06

Step 1: Visual Inspection Begin by inspecting the injector wiring harness from the ECM to Cylinder #2. Look for visible damage, abrasion points where the harness contacts the valve cover, or oil contamination on connectors. On used excavators, check for previous repair attempts like electrical tape or aftermarket splices that may have degraded.

Step 2: Electrical Testing Disconnect the Cylinder #2 injector connector and measure solenoid resistance using a digital multimeter. Typical specification is 0.3-0.6 ohms at room temperature. Also check for short to ground by measuring resistance between each injector terminal and engine ground—readings should be infinite (open circuit).

Step 3: ECM and Harness Verification Using Doosan DMS diagnostic software or a compatible scan tool, perform an injector cut-out test to isolate the fault. If the code persists with a known-good injector installed, inspect the ECM connector pins for corrosion and test the harness continuity from ECM to injector. Replace damaged sections rather than entire harnesses when possible to reduce costs on used equipment.

Step 4: Component Replacement If diagnostics confirm injector failure, replace the Cylinder #2 fuel injector with OEM or quality aftermarket parts. Always replace injector sealing washers and torque to specification (typically 45-50 Nm). Clear codes and perform a road test under load.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Doosan service manual and consider professional assistance for complex electrical diagnostics or fuel system repairs.