What is Komatsu PC200LC-7 Fault Code E218?

Fault Code E218 on the Komatsu PC200LC-7 indicates a malfunction in the hydraulic oil temperature sensor circuit, specifically detecting an abnormally high voltage signal or open circuit condition in the sensor wiring. This code is stored in the machine's Electronic Control Module (ECM) when the temperature sensor circuit voltage exceeds the manufacturer's predetermined threshold, typically above 4.8-5.0 volts for more than 2 seconds.

The hydraulic oil temperature sensor plays a critical role in protecting the PC200LC-7's hydraulic system by monitoring operating temperatures and preventing thermal damage to seals, pumps, and control valves. When this code activates, the ECM may default to substitute temperature values, potentially affecting hydraulic response times and limiting machine performance to protect components from thermal overload.

Common Symptoms

• Warning light illumination on the instrument cluster with reduced hydraulic system responsiveness
• Automatic engine derating or speed limitation to prevent hydraulic system overheating
• Erratic hydraulic oil temperature gauge readings showing unusually high or fluctuating temperatures
• Loss of automatic warm-up function during cold starts, affecting initial operational efficiency
• Stored diagnostic trouble code visible through the monitor panel or diagnostic software connection

Potential Causes

The E218 code typically results from electrical circuit failures rather than actual temperature problems. Broken or frayed wiring in the harness running from the hydraulic tank to the ECM is extremely common in used PC200LC-7 excavators, particularly where the harness routes near the swing bearing or along the boom base where vibration and flexing occur.

Corroded or moisture-infiltrated connectors at the sensor terminals frequently cause high resistance or open circuits. The hydraulic oil temperature sensor itself may fail internally, especially in machines with 5,000+ operating hours. ECM pin corrosion at the temperature sensor input terminals can also generate false high-voltage readings.

How to Troubleshoot and Fix Code E218

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor mounted on the hydraulic tank (typically near the suction strainer). Inspect the sensor connector for corrosion, bent pins, or oil contamination. Check the entire wiring harness from sensor to ECM for abrasion points, particularly where cables contact frame members or pass through grommets.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure resistance across the sensor terminals. At room temperature (20°C/68°F), resistance should read approximately 2,000-3,000 ohms. Check for continuity in the harness wiring between sensor connector and ECM pins (consult service manual for specific pin locations). Measure voltage at the disconnected harness connector—you should see approximately 5 volts reference voltage from the ECM.

Step 3: Component Replacement If resistance values are out of specification or the circuit shows infinite resistance (open circuit), replace the temperature sensor (Komatsu part number 7861-93-3320 or equivalent). For used excavators with harness damage, repair or replace the affected wiring section using proper gauge wire and weatherproof connectors. Clear codes using Komatsu diagnostic software and monitor during operation.

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu PC200LC-7 service manual and consider professional technician assistance for complex electrical diagnostics and repairs.