What is Doosan DX215-9C Fault Code E520638-03 (P2671)?

Fault code E520638-03 (P2671) indicates a malfunction in the Cylinder 6 Glow Plug Circuit on the Doosan DX215-9C excavator. This diagnostic trouble code (DTC) specifically signals that the Engine Control Module (ECM) has detected an abnormal electrical condition in the glow plug system for cylinder number 6, typically a circuit voltage issue or excessive resistance.

In Doosan's DX215-9C model equipped with Doosan DL08 diesel engines, the glow plug system is critical for cold-start performance and proper combustion chamber temperature regulation. When this circuit fails, cylinder 6 may experience incomplete combustion, increased white smoke emissions, and rough idling—particularly problematic in colder climates where used excavators often operate with aging electrical components.

Common Symptoms

• Check Engine Light (CEL) illuminated on the instrument cluster with P2671 stored in ECM memory
• Difficult cold starting or extended cranking times, especially in temperatures below 40°F (4°C)
• Excessive white or gray smoke from the exhaust during initial startup
• Rough engine idle for the first 2-5 minutes of operation until the engine reaches operating temperature
• Reduced engine power or hesitation during the warm-up phase

Potential Causes

The most common technical failures triggering E520638-03 on used DX215-9C excavators include:

• Failed glow plug in cylinder 6 due to carbon buildup or element burnout (common after 3,000-5,000 operating hours)
• Damaged wiring harness or corroded connectors between the glow plug relay module and cylinder 6 glow plug—especially at harness rub points near the valve cover
• Faulty glow plug relay or glow plug control module providing inconsistent voltage supply
• Open circuit or high resistance in the cylinder 6 glow plug circuit (typically should read 0.5-2.0 ohms)
• ECM internal fault (rare, but possible in machines with water intrusion history)

How to Troubleshoot and Fix Code E520638-03 (P2671)

Step 1: Visual Inspection Locate the glow plug harness on the cylinder head. Inspect all connectors to cylinder 6 for corrosion, moisture, or physical damage. Check for harness chafing against the valve cover or fuel lines—a known wear point on used DX215-9C models.

Step 2: Resistance Testing Disconnect the glow plug connector for cylinder 6. Using a digital multimeter, measure resistance between the glow plug terminal and ground. A healthy glow plug reads 0.5-2.0 ohms. Readings above 5 ohms or infinite resistance indicate glow plug failure.

Step 3: Circuit Voltage Check With the ignition in the "ON" position (glow plug cycle active), measure voltage at the glow plug connector. You should see 10-12 volts for 15-30 seconds. No voltage indicates a relay module or wiring harness fault.

Step 4: Inspect Relay and Module Test the glow plug relay (typically located in the engine compartment fuse box) by swapping with an identical relay. If the code clears, replace the relay. For used excavators, also check relay socket pins for corrosion.

Step 5: Clear Code and Verify After repairs, use Doosan diagnostic software (DMS-5) or a compatible J1939 scanner to clear the fault code. Perform a cold-start test to verify proper glow plug operation.

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Disclaimer: This guide provides general troubleshooting steps for informational purposes. Always consult the official Doosan service manual for your specific machine serial number, and consider professional diagnostic services for complex electrical issues on used heavy equipment.