What is Komatsu PC110-8M0 Fault Code E-17?

Fault Code E-17 on the Komatsu PC110-8M0 excavator indicates a Hydraulic Oil Temperature Sensor Circuit malfunction. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects an abnormal voltage signal from the hydraulic oil temperature sensor, typically indicating an open circuit, short circuit, or sensor degradation.

The hydraulic oil temperature sensor plays a critical role in the PC110-8M0's operational safety system. It continuously monitors the temperature of the hydraulic fluid to prevent overheating that could damage pumps, cylinders, and seals. When this sensor circuit fails, the ECM cannot accurately assess whether the hydraulic system is operating within safe temperature parameters (typically 40-80°C operating range), potentially leading to component damage or reduced machine lifespan.

Common Symptoms

When Code E-17 is active on your Komatsu PC110-8M0, you may experience:

• Warning light illumination on the instrument panel, often accompanied by a hydraulic temperature icon or general fault indicator
• Erratic or stuck hydraulic temperature gauge readings showing abnormally high, low, or unchanging temperatures
• Reduced hydraulic system performance as the ECM may enter a protective derate mode limiting pump output
• Intermittent alarm beeping in the operator cabin signaling system faults
• Slower cycle times for boom, arm, and bucket functions due to conservative ECM programming during sensor faults

Potential Causes

The most common technical causes for Code E-17 on used PC110-8M0 excavators include:

• Sensor connector corrosion at the hydraulic tank mounting point, especially on machines operating in wet or coastal environments
• Wiring harness damage near the hydraulic tank where harness routing creates friction points against metal edges during machine vibration
• Failed hydraulic oil temperature sensor due to thermal cycling fatigue (common after 5,000+ operating hours)
• Broken or frayed sensor wiring in the harness section running along the undercarriage where debris impact is frequent
• ECM internal circuit fault (less common but possible on higher-hour machines with prior electrical issues)
• Corrosion or moisture intrusion in sensor terminal pins causing intermittent open circuits

How to Troubleshoot and Fix Code E-17

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor on the hydraulic tank (typically mounted on the left side near the return filter). Inspect the sensor connector for corrosion, bent pins, or moisture. On used excavators, this connector frequently accumulates dirt and moisture. Clean with electrical contact cleaner and check for physical damage to the sensor body or mounting threads.

Step 2: Electrical Testing Disconnect the sensor two-pin connector and use a digital multimeter to measure sensor resistance. At room temperature (20°C), resistance should typically read between 2,000-3,000 ohms (consult your service manual for exact specifications). Also check the wiring harness for continuity from the sensor connector back to the ECM. Measure resistance; it should be less than 5 ohms. Check for shorts to ground by measuring resistance between each wire and the machine frame—readings should be infinite (open circuit).

Step 3: Harness Inspection for Used Machines For used excavators, trace the sensor harness routing from the hydraulic tank toward the ECM. Pay special attention to areas where the harness passes near sharp edges, swing post mounting points, or hydraulic hoses. Look for chafing, cracking, or exposed copper wire. This model commonly experiences harness wear at the transition point near the left track frame.

Step 4: Sensor Replacement and Verification If testing indicates sensor failure, replace with a genuine Komatsu hydraulic temperature sensor (part number available through dealer). Before installation, apply dielectric grease to connector pins to prevent future corrosion. After installation, clear the fault code using Komatsu diagnostic software (KOMTRAX) or a compatible scan tool, then operate the machine through a full warm-up cycle while monitoring live data to confirm proper sensor voltage (typically 0.5-4.5V range depending on temperature).

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Disclaimer: This guide provides general diagnostic information for Code E-17. Hydraulic and electrical system repairs should be performed by qualified technicians. Always consult the official Komatsu PC110-8M0 service manual and follow proper safety lockout/tagout procedures before performing diagnostics or repairs.