Komatsu PC200-7 Fault Code E113: Complete Diagnostic Guide

What is Komatsu PC200-7 Fault Code E113?

Fault Code E113 on the Komatsu PC200-7 indicates a malfunction in the engine coolant temperature sensor circuit. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal voltage signal from the coolant temperature sensor, typically caused by an open circuit, short circuit, or sensor failure.

The coolant temperature sensor plays a critical role in the PC200-7's performance. It provides real-time engine temperature data to the ECM, which adjusts fuel injection timing, idle speed, and activates cooling fan operation. When this sensor circuit fails, the ECM cannot properly regulate engine temperature, potentially leading to overheating, reduced power output, or engine protection modes that derate performance to prevent catastrophic damage.

Common Symptoms

When Code E113 is active on your Komatsu PC200-7, operators typically experience:

• Engine warning light illuminated on the instrument cluster
• Abnormal cooling fan operation (running continuously or not engaging when needed)
• Erratic engine idle or rough running, especially during cold starts
• Loss of engine power or derate mode activation to protect the engine
• Inaccurate temperature gauge readings showing extremely high or low temperatures that don't match actual engine conditions

Potential Causes

The most common technical causes for Code E113 on used PC200-7 excavators include:

• Failed coolant temperature sensor due to age, thermal cycling, or internal element degradation
• Damaged wiring harness near the thermostat housing where vibration and heat cause insulation breakdown
• Corroded or loose connector pins at the sensor connection point (common in machines operating in wet or corrosive environments)
• Broken or chafed wires at known rub points along the left side engine harness near the injection pump
• ECM internal fault (rare, but possible in high-hour machines)
• Poor ground connection in the sensor circuit causing intermittent voltage readings

How to Troubleshoot and Fix Code E113

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located near the thermostat housing on the engine block. Check for physical damage, coolant leaks around the sensor base, and corrosion on the connector. On used excavators, examine the entire wiring harness from sensor to ECM for signs of chafing, particularly where the harness contacts metal brackets or passes near hot engine components.

Step 2: Electrical Testing Using a digital multimeter, disconnect the coolant temperature sensor connector. Measure resistance across the sensor terminals with the engine cold (should read approximately 2,000-3,000 ohms at 68°F/20°C) and warm (should decrease to 200-400 ohms at 176°F/80°C). If readings are out of specification or show infinite resistance (open circuit), replace the sensor. Check for supply voltage at the harness connector—you should see approximately 5 volts from the ECM.

Step 3: Harness and Ground Verification Inspect connector terminals for corrosion or bent pins. Clean contacts with electrical contact cleaner and dielectric grease. Verify continuity between the sensor connector and ECM pins using wiring diagrams. Check the ground circuit resistance—it should be less than 1 ohm. For used machines, pay special attention to harness sections that show heat discoloration or brittle insulation.

Step 4: Advanced Diagnostics If sensor and wiring check out, connect Komatsu diagnostic software (KOMTRAX or compatible scan tool) to verify ECM parameters and perform active tests. Clear codes and monitor live data during a heat cycle to confirm proper sensor operation.

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific machine serial number and seek assistance from qualified technicians for complex electrical repairs or if you're uncertain about any procedure.