Komatsu PC400-6 Fault Code E213: Complete Diagnostic Guide

What is Komatsu PC400-6 Fault Code E213?

Fault Code E213 on the Komatsu PC400-6 indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Engine Control Module (ECM). This code specifically relates to the coolant temperature sensor sending irregular voltage signals or detecting temperatures outside the normal operating parameters.

The ECM relies on accurate coolant temperature data to optimize fuel injection timing, engine protection protocols, and overall performance. On the PC400-6's SAA6D125E-3 engine, this sensor is critical for preventing overheating and maintaining efficient combustion. When E213 triggers, the ECM may default to a predetermined temperature value, potentially affecting engine performance and fuel economy.

Common Symptoms

When Code E213 is active, operators typically experience:

• Warning light illumination on the instrument cluster (engine or temperature indicator)
• Engine derate or reduced power output as a protective measure
• Erratic temperature gauge readings or gauge stuck at cold/hot positions
• Hard starting when the engine is cold due to incorrect fuel mapping
• Increased fuel consumption as the ECM operates in failsafe mode

Potential Causes

The most common technical causes for E213 on used PC400-6 excavators include:

• Coolant temperature sensor failure due to age-related degradation or internal short/open circuit
• Damaged wiring harness near the sensor, particularly where the harness contacts the engine block or frame (known rub point on this model)
• Corroded or loose connector pins at the sensor plug, especially on machines with high operating hours
• ECM internal fault (less common) affecting the temperature input circuit
• Coolant contamination causing sensor element fouling or coating
• Ground circuit issues between the sensor and ECM

How to Troubleshoot and Fix Code E213

Step 1: Visual Inspection Begin by locating the coolant temperature sensor on the engine block (typically near the thermostat housing). Inspect the wiring harness for visible damage, chafing, or melted insulation. Check the connector for corrosion, bent pins, or moisture intrusion—common issues on used excavators operating in harsh environments.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance at various temperatures. At 20°C (68°F), resistance should typically read 2,000-3,000 ohms; at 80°C (176°F), approximately 300-400 ohms. Compare readings against Komatsu specifications. Also check for continuity in the wiring harness from sensor to ECM.

Step 3: Voltage Signal Check With the sensor connected and ignition on (engine off), backprobe the sensor connector to measure reference voltage from the ECM (should be approximately 5 volts). If voltage is absent or incorrect, suspect wiring issues or ECM problems.

Step 4: Component Replacement If the sensor tests faulty, replace it with a genuine Komatsu part or quality equivalent. Before installation, clean the sensor bore and apply appropriate thread sealant. For used excavators, always replace the connector pigtail if corrosion is present, as this prevents recurring failures.

Step 5: Clear Codes and Verify After repairs, use Komatsu diagnostic software (KOMTRAX or compatible scan tool) to clear the fault code. Run the engine through temperature cycles and monitor for code recurrence.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific machine serial number and consider professional assistance for complex electrical diagnostics or if you're unfamiliar with high-voltage systems.