Komatsu PC800SE-8R Fault Code E-19: Complete Diagnostic Guide

What is Komatsu PC800SE-8R Fault Code E-19?

Fault Code E-19 on the Komatsu PC800SE-8R 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 relates to the temperature monitoring system that protects the engine from overheating damage.

The coolant temperature sensor sends voltage signals to the ECM, which uses this data to regulate fuel injection timing, engine speed, and activate warning systems. On the PC800SE-8R's SAA6D170E-5 engine, maintaining accurate temperature readings is critical for preventing catastrophic engine damage and ensuring optimal hydraulic system performance. When E-19 triggers, the ECM may enter a protective derate mode to prevent overheating.

Common Symptoms

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

• Engine warning light illuminated on the monitor panel, often accompanied by an audible alarm
• Reduced engine power or automatic derate mode limiting machine performance
• Erratic temperature gauge readings showing unusually high, low, or fluctuating coolant temperatures
• Difficulty starting the engine, particularly in cold weather conditions
• Increased fan engagement as the ECM attempts to compensate for perceived high temperatures

Potential Causes

The most common technical causes for E-19 on used PC800SE-8R excavators include:

• Failed coolant temperature sensor due to internal element degradation (common after 8,000+ operating hours)
• Damaged wiring harness near the sensor connector, particularly where the harness routes along the engine block and experiences heat cycling
• Corroded or loose electrical connections at the sensor plug or ECM terminals
• Low coolant level causing inaccurate temperature readings or actual overheating
• ECM software glitches or internal ECM failure (less common but possible in high-hour machines)
• Short circuits in the sensor wiring caused by harness rubbing against engine components

How to Troubleshoot and Fix Code E-19

Step 1: Visual Inspection Begin by checking coolant level in the radiator and overflow tank. Inspect the coolant temperature sensor (located on the engine block near the thermostat housing) and its wiring harness for obvious damage, corrosion, or oil contamination. On used excavators, pay special attention to connector pins for green corrosion or bent terminals.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Test the harness continuity from sensor connector to ECM and check for short circuits to ground (should read infinite resistance).

Step 3: Sensor Replacement and Verification If the sensor fails resistance testing or harness shows damage, replace the faulty component using genuine Komatsu parts (part number specific to PC800SE-8R). After replacement, clear codes using Komatsu diagnostic software (KOMTRAX) or a compatible scan tool, then run the engine through temperature cycles to verify repair.

Step 4: Advanced Diagnostics If the code persists after sensor and harness replacement, inspect ECM connector pins for corrosion and consider ECM voltage supply testing (typically 5V reference signal). For used machines with extensive hours, consider professional ECM bench testing.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu service manual for your specific serial number and consider professional assistance for complex electrical diagnostics or if you're unfamiliar with high-voltage systems.