Komatsu PC210LC-10 Fault Code E-15: Complete Diagnostic Guide

What is Komatsu PC210LC-10 Fault Code E-15?

Fault Code E-15 on the Komatsu PC210LC-10 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 monitors the thermistor-type sensor that provides critical temperature data to the ECM for proper fuel injection timing, engine protection, and hydraulic oil warm-up control.

This fault is particularly critical for the PC210LC-10's SAA6D107E-1 engine because improper temperature readings can trigger unnecessary derating (reduced power output), prevent the engine from reaching optimal operating temperature, or fail to warn operators of genuine overheating conditions. In used excavators, this code frequently appears due to sensor degradation or wiring harness issues rather than actual cooling system failures.

Common Symptoms

When Code E-15 is active, operators typically experience:

• Engine warning light illuminated on the monitor panel with code display
• Engine fails to reach normal operating temperature or shows erratic temperature fluctuations
• Hydraulic system responds sluggishly during cold starts due to improper warm-up protocol
• Auto-idle function may not engage properly or operates irregularly
• In severe cases, the ECM may initiate power derate mode as a protective measure

Potential Causes

The most common technical causes for Code E-15 on used PC210LC-10 excavators include:

• Coolant temperature sensor internal resistance failure (typical after 6,000-8,000 operating hours)
• Corroded or loose connector pins at the sensor harness (2-pin connector near thermostat housing)
• Damaged wiring between the sensor and ECM, particularly at harness routing points near the turbocharger
• ECM supply voltage issues to the sensor circuit (should be 5V reference)
• Contaminated coolant causing sensor element coating and false readings
• Previous repair attempts using incorrect sensor specifications (aftermarket vs. OEM)

How to Troubleshoot and Fix Code E-15

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the cylinder head near the thermostat housing. Check for physical damage, coolant leaks, or corrosion on the 2-pin connector. On used excavators, pay special attention to harness chafing where it routes over the engine block.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across the sensor terminals. At 68°F (20°C), resistance should read approximately 2.3-2.7 kΩ. Verify the ECM provides 5V reference voltage at the harness connector with the sensor disconnected.

Step 3: Wiring Harness Verification Perform continuity tests between the sensor connector and ECM pins (typically E2-31 and E2-32). Check for shorts to ground or voltage. Inspect harness for oil contamination or heat damage, common failure points on high-hour machines.

Step 4: Component Replacement If sensor resistance is out of specification or wiring shows damage, replace the faulty component using Komatsu OEM parts (P/N 6754-61-6210 for sensor). After replacement, clear codes using Komatsu diagnostic software (KOMTRAX) or compatible scan tool and verify code does not return after a 30-minute operational test.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the Komatsu PC210LC-10 service manual and consider professional diagnostic services for complex electrical issues or if you lack experience with heavy equipment repair.