Komatsu PC200-7 Fault Code E-19: Complete Diagnostic Guide

What is Komatsu PC200-7 Fault Code E-19?

Komatsu PC200-7 Fault Code E-19 indicates a malfunction in the hydraulic oil temperature sensor circuit. This code triggers when the Engine Control Module (ECM) detects an abnormal voltage signal from the hydraulic oil temperature sensor, typically located in the hydraulic tank or main control valve assembly.

This sensor plays a critical role in monitoring hydraulic fluid temperature to prevent overheating and maintain optimal system performance. On the PC200-7, hydraulic oil temperature directly affects viscosity, component lubrication, and overall machine efficiency. When E-19 appears, the ECM may default to fail-safe mode, potentially limiting machine performance to protect the hydraulic system from damage.

Common Symptoms

When Code E-19 is active, operators typically experience:

• Warning light illuminated on the instrument panel (hydraulic oil temperature indicator)
• Reduced hydraulic performance or sluggish boom, arm, and bucket movements
• Intermittent or continuous alarm beeping from the cab monitor
• Inaccurate temperature readings on the display (showing abnormally high or low temperatures)
• Possible automatic engine derate or shutdown if the ECM cannot verify safe operating temperature

Potential Causes

The most common technical reasons for E-19 on used PC200-7 excavators include:

• Failed hydraulic oil temperature sensor due to internal component degradation or contamination exposure
• Damaged or corroded wiring harness between the sensor and ECM, particularly at connection points near the hydraulic tank
• Loose or corroded connector pins at the sensor plug—common in machines operating in wet or corrosive environments
• Shorted or open circuit in the sensor signal wire, often caused by harness chafing against frame components
• ECM software glitches or internal ECM circuit failure (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code E-19

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor (typically mounted on the hydraulic tank). Inspect the wiring harness for obvious damage, cuts, or wear points where cables contact the frame. Check all connector pins for corrosion, bent terminals, or hydraulic oil contamination.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across the sensor terminals. Compare readings against Komatsu specifications (typically 200-400 ohms at room temperature). Check for continuity in the wiring from sensor to ECM. Measure supply voltage at the connector (should be approximately 5 volts from ECM).

Step 3: Component Replacement If resistance values fall outside specifications or wiring shows damage, replace the faulty component. For used excavators, always inspect connector seals and apply dielectric grease to prevent future corrosion. After repairs, clear codes using Komatsu diagnostic software and perform a functional test under operating temperature.

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Disclaimer: This guide provides general troubleshooting information. Always consult factory service manuals and consider professional diagnostic assistance for complex electrical issues.