What is Komatsu PC110-7 Fault Code E-17?

Komatsu PC110-7 fault code E-17 indicates a hydraulic oil temperature sensor circuit malfunction or abnormal temperature reading in the hydraulic system. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects either an open circuit, short circuit, or implausible voltage signal from the hydraulic oil temperature sensor located in the main hydraulic tank.

This code is critical for the PC110-7 because the hydraulic system operates within a specific temperature range (typically 40-80°C/104-176°F). Excessive temperatures can cause rapid degradation of hydraulic fluid, seal failure, and reduced machine efficiency. The ECM uses this sensor data to protect the hydraulic pump and circuit components from thermal damage.

Common Symptoms

When fault code E-17 is active on your Komatsu PC110-7, you may experience:

• Hydraulic oil temperature warning light illuminated on the instrument panel (amber or red depending on severity)
• Reduced hydraulic responsiveness or sluggish boom/arm/bucket movements as the system enters protection mode
• Machine derate or shutdown in severe cases to prevent hydraulic system damage
• Inaccurate hydraulic temperature readings on the monitor display (reading abnormally high, low, or erratic)
• Audible warning alarm accompanying the visual indicators

Potential Causes

The most common technical causes for E-17 on used PC110-7 excavators include:

• Damaged or corroded sensor connector at the hydraulic tank (common failure point due to moisture ingress and vibration)
• Faulty hydraulic oil temperature sensor with internal resistance drift (typical after 5,000+ operating hours)
• Wiring harness chafing near the swing motor area or along the undercarriage where cables rub against frame members
• Loose or corroded ground connections affecting sensor circuit integrity
• Contaminated hydraulic oil causing actual overheating, triggering legitimate high-temperature readings
• ECM internal fault (rare, but possible in older machines with 8,000+ hours)

How to Troubleshoot and Fix Code E-17

Step 1: Visual Inspection Begin by inspecting the hydraulic oil temperature sensor located on the right side of the main hydraulic tank. Check the connector pins for corrosion, bent terminals, or oil contamination. On used excavators, examine the entire wiring harness from sensor to ECM for abrasion points, particularly where it passes near rotating components.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to check sensor resistance. At 25°C (77°F), resistance should read approximately 2.0-3.0 kΩ (consult your PC110-7 service manual for exact specifications). Check for continuity in the harness wiring and verify supply voltage (typically 5V reference) from the ECM at the sensor connector.

Step 3: Advanced Diagnostics Connect Komatsu KOMTRAX diagnostic software or a compatible scan tool to monitor live sensor data. Compare actual hydraulic oil temperature (measured with an infrared thermometer) against displayed values. A variance greater than 10°C indicates sensor replacement is needed.

Step 4: Corrective Action If the sensor tests faulty, replace with a genuine Komatsu part number 7861-93-3320 or equivalent. Before reassembly, apply dielectric grease to connector terminals to prevent future corrosion. For used machines, consider replacing the entire sensor-to-ECM harness section if wear is evident.

Disclaimer: This guide provides general troubleshooting information for Komatsu PC110-7 excavators. Always consult the manufacturer's official service manual and consider professional diagnostic services for complex electrical issues. Improper repairs may void warranties or cause additional machine damage.