Komatsu PC210LC-7 Fault Code E116: Complete Diagnostic Guide

What is Komatsu PC210LC-7 Fault Code E116?

Fault Code E116 indicates a malfunction in the engine coolant temperature sensor circuit, specifically detecting an abnormal voltage signal or open/short circuit condition in the water temperature sensor system. This code is triggered when the Engine Control Module (ECM) receives sensor readings outside the normal operating range (typically 0.2-4.8V) from the coolant temperature sensor located on the engine block.

For the Komatsu PC210LC-7 equipped with the SAA6D107E-1 engine, this code is critical because the ECM relies on accurate coolant temperature data to control fuel injection timing, idle speed, and engine protection protocols. When E116 activates, the system defaults to a predetermined temperature value, which can lead to inefficient combustion, increased emissions, and potential engine protection mode activation.

Common Symptoms

When Code E116 is active on your PC210LC-7, operators typically experience:

• Warning lamp illumination on the instrument cluster with reduced engine power output
• Hard starting conditions, especially in cold weather, due to incorrect fuel mapping
• Rough idle or hunting as the ECM compensates with default temperature values
• Black or white exhaust smoke from improper fuel-to-air ratios
• Engine derate mode engaging prematurely, limiting machine to 1,500 RPM or below

Potential Causes

The most common technical causes for E116 on used PC210LC-7 excavators include:

• Coolant temperature sensor failure due to thermal cycling and age-related deterioration
• Wiring harness damage at known rub points near the engine mount brackets and fuel filter housing
• Corroded or loose connector pins at the sensor plug (2-pin Deutsch connector)
• ECM internal fault affecting the sensor circuit (rare but possible on high-hour machines)
• Damaged sensor threads causing coolant leaks and sensor malfunction
• Ground circuit issues at chassis ground points G101 or G102

How to Troubleshoot and Fix Code E116

Step 1: Visual Inspection Locate the coolant temperature sensor on the left side of the engine block near the thermostat housing. Inspect the wiring harness for obvious damage, particularly where it passes over the engine mount. Check the connector for corrosion, pushed-back pins, or coolant intrusion—common on used excavators operating in harsh environments.

Step 2: Electrical Testing Disconnect the sensor connector and measure resistance across the sensor terminals using a digital multimeter. At 68°F (20°C), resistance should read approximately 2,300-2,700 Ω. If readings show infinite resistance (open circuit) or near-zero (short circuit), replace the sensor. Also test harness continuity from the connector back to ECM pins and verify less than 5 Ω resistance.

Step 3: Live Voltage Check With the ignition on and sensor disconnected, measure supply voltage at the harness connector. You should see approximately 5V reference voltage from the ECM. If voltage is absent or incorrect, trace the circuit for damaged wires or check ECM power supply circuits.

Step 4: Repair and Verify Replace faulty components and secure any repaired harness sections away from heat and friction points using proper loom protection. Clear codes using Komatsu KOMTRAX diagnostic software or compatible scan tool, then run the engine through temperature cycles to confirm repair.

Disclaimer: This guide provides general troubleshooting steps. For critical repairs or persistent issues, consult a certified Komatsu technician or authorized service center. Improper diagnosis may result in engine damage or safety hazards.