What is Komatsu PC210-7 Fault Code E116?

Fault Code E116 on the Komatsu PC210-7 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 water temperature sensor system that monitors engine operating temperature and sends critical data to the ECM for fuel injection timing, fan control, and overheating protection.

This fault is particularly critical on the PC210-7 because the SAA6D107E-1 engine relies heavily on accurate temperature data to prevent thermal damage and optimize hydraulic pump performance. When the ECM cannot verify coolant temperature, it may force the machine into a protective derate mode, limiting engine power and hydraulic responsiveness to prevent catastrophic engine failure.

Common Symptoms

• Engine warning light illuminated on the instrument cluster, often accompanied by a temperature gauge malfunction
• Reduced engine power or automatic derate limiting maximum RPM to approximately 1,500-1,800 RPM
• Cooling fan running continuously at high speed, even when engine temperature appears normal
• Difficulty starting in cold conditions or irregular idle when the engine is cold
• Error message displayed on the multi-monitor screen indicating temperature sensor issues

Potential Causes

The most common technical causes for Code E116 on used PC210-7 excavators include:

• Failed coolant temperature sensor due to internal resistance drift (common after 5,000+ operating hours)
• Corroded or loose connector pins at the temperature sensor harness connection point near the thermostat housing
• Damaged wiring harness between the sensor and ECM, particularly where the harness passes over the engine valve cover (known rub point on this model)
• Contaminated coolant causing sensor element coating or electrical grounding issues
• ECM internal fault in the temperature input circuit (less common, but possible in high-hour machines)
• Poor ground connection at engine block grounding points, creating erratic sensor readings

How to Troubleshoot and Fix Code E116

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the engine block near the thermostat housing. Check for coolant leaks, corrosion on the connector, or physical damage. On used excavators, examine the wiring harness for wear marks, especially where it contacts the engine or frame—this is a common failure point on PC210-7 models with 4,000+ hours.

Step 2: Electrical Testing Using a digital multimeter, disconnect the temperature sensor connector and measure resistance across the sensor terminals. At 68°F (20°C), resistance should read approximately 2,000-3,000 ohms. Compare readings against Komatsu specifications. Next, check for 5-volt reference voltage at the harness connector from the ECM with the key in the ON position.

Step 3: Harness and Ground Verification Inspect the entire sensor harness for continuity and check for shorts to ground. Verify engine ground strap connections are clean and tight. In used machines, corrosion at grounding points frequently causes intermittent fault codes. Clean all connections with electrical contact cleaner.

Step 4: Component Replacement or ECM Diagnostics If sensor resistance is out of specification or harness testing reveals wiring damage, replace the faulty component. Use genuine Komatsu parts (Part #6738-81-7120 for the sensor) to ensure proper ECM communication. If all components test correctly, connect Komatsu diagnostic software (KOMTRAX Plus or KES) to check for ECM programming issues or internal circuit failures.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and seek professional assistance from certified technicians for complex electrical diagnostics or ECM repairs.