What is Komatsu PC210LC-7 Fault Code E-19?

Fault Code E-19 on the Komatsu PC210LC-7 indicates a malfunction in the hydraulic oil temperature sensor circuit or an abnormal temperature reading in the hydraulic system. This code is triggered when the engine control module (ECM) detects either an open circuit, short circuit, or out-of-range signal from the hydraulic oil temperature sensor, which monitors the working temperature of the hydraulic fluid in the main system.

The hydraulic oil temperature sensor plays a critical role in protecting the PC210LC-7's hydraulic components from thermal damage. When hydraulic oil exceeds safe operating temperatures (typically above 95-100°C or 203-212°F), efficiency drops dramatically, seals deteriorate faster, and component wear accelerates. The ECM uses this sensor data to warn operators and potentially limit machine functions to prevent catastrophic hydraulic system failure—especially important in used excavators where hydraulic components may already show wear.

Common Symptoms

When Code E-19 is active on your Komatsu PC210LC-7, you may experience:

• Warning light illumination on the monitor panel, often accompanied by an audible alarm
• Hydraulic system overheating with reduced hydraulic response or sluggish operation
• Temperature gauge reading abnormally high or low (or not reading at all)
• Reduced engine power or machine going into derate/limp mode to protect hydraulics
• Intermittent code activation, especially during heavy operation or hot ambient conditions

Potential Causes

The most common technical reasons for E-19 on used PC210LC-7 excavators include:

• Failed hydraulic oil temperature sensor due to internal component degradation (common after 5,000+ hours)
• Damaged or corroded wiring harness connecting the sensor to the ECM—particularly at connector pins exposed to hydraulic oil contamination
• Frayed wiring at known rub points near the hydraulic tank or along the main chassis frame
• Poor electrical ground connection at the sensor mounting location
• Actual hydraulic oil overheating caused by clogged hydraulic oil cooler, low oil level, or failing cooling fan
• ECM calibration issues or internal ECM fault (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code E-19

Step 1: Visual Inspection Begin with a thorough inspection of the hydraulic oil temperature sensor located on the hydraulic tank. Check the sensor body for physical damage, oil leaks, or loose mounting. Inspect the wiring harness from sensor to ECM, paying special attention to areas where wires contact metal surfaces or pass near rotating components. On used excavators, look for abraded insulation, corroded connectors, and oil-soaked wiring that may cause intermittent faults.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. At room temperature (20°C/68°F), resistance should typically read between 2,000-3,000 ohms (consult your PC210LC-7 service manual for exact specifications). Test the wiring harness continuity from sensor connector to ECM pins—check for opens or shorts to ground. Measure supply voltage at the sensor connector with ignition on; you should see approximately 5 volts from the ECM reference circuit.

Step 3: Check Actual Hydraulic Temperature Before replacing components, verify the actual hydraulic oil temperature using an infrared thermometer on the hydraulic tank surface. If oil temperature genuinely exceeds 95°C (203°F), address the root cause: inspect the hydraulic oil cooler for debris blockage, verify cooling fan operation, check hydraulic oil level, and examine the system for restrictions causing excessive heat generation.

Step 4: Component Replacement and Verification If sensor readings are out of specification or wiring shows damage, replace the faulty component with genuine Komatsu parts or OEM-equivalent sensors. After replacement, clear fault codes using Komatsu diagnostic software (KOMTRAX Plus) or a compatible scan tool. Cycle the ignition, operate the machine through normal work cycles, and monitor for code recurrence. For used machines, consider applying dielectric grease to all electrical connectors to prevent future corrosion.

Disclaimer: This guide provides general diagnostic information for the Komatsu PC210LC-7. Hydraulic and electrical system repairs should be performed by qualified technicians with proper training, tools, and access to manufacturer service literature. Always consult the official Komatsu service manual and follow safety protocols when diagnosing fault codes on heavy equipment.