Komatsu PC800-7 Fault Code E-19: Complete Diagnostic Guide

What is Komatsu PC800-7 Fault Code E-19?

Fault Code E-19 on the Komatsu PC800-7 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 coolant temperature monitoring system, which is critical for preventing engine overheating and maintaining optimal operating temperatures.

The ECM continuously monitors signals from the coolant temperature sensor to regulate fuel injection timing, engine speed, and cooling fan operation. When the sensor provides readings outside the normal operating range (typically -40°C to 150°C), or when circuit voltage falls outside specified parameters (usually 0.5V to 4.5V), the E-19 code triggers. For the PC800-7's SAA6D140E-3 engine, proper temperature monitoring is essential to prevent catastrophic engine damage and maintain the machine's 400+ horsepower output efficiently.

Common Symptoms

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

• Engine warning light illuminated on the instrument cluster with possible audible alarm
• Reduced engine power or automatic derate mode to protect the engine from potential overheating
• Erratic temperature gauge readings showing unusually high, low, or fluctuating coolant temperatures
• Cooling fan running continuously at maximum speed regardless of actual engine temperature
• Difficulty starting in cold conditions or rough idle when the engine is cold

Potential Causes

The most common technical causes for E-19 on used PC800-7 excavators include:

• Faulty coolant temperature sensor due to internal element degradation (common after 8,000+ operating hours)
• Damaged or corroded wiring harness at connector points, especially near the engine block where heat and vibration cause wear
• Corroded sensor connector pins from coolant leaks or moisture intrusion in the engine compartment
• Open or short circuit in the sensor wiring, particularly at harness rub points along the engine valley
• ECM internal fault (rare) affecting the temperature sensor input circuit
• Low coolant level causing intermittent sensor exposure and false readings

How to Troubleshoot and Fix Code E-19

Step 1: Visual Inspection Begin by checking the 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 coolant contamination. On used excavators, pay special attention to connector terminals for green corrosion or bent pins.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. At 20°C (68°F), resistance should read approximately 2,000-3,000 ohms (consult your service manual for exact specifications). Check for continuity in the wiring from sensor to ECM connector pins. Measure supply voltage at the sensor connector with ignition on—it should read approximately 5 volts.

Step 3: Advanced Diagnostics Connect Komatsu KOMTRAX or compatible diagnostic software to read live sensor data and compare actual coolant temperature with sensor readings. Test the sensor under varying temperature conditions using a heat gun while monitoring resistance values. For used machines, inspect harness routing for wear points against engine components or frame members.

Step 4: Repair or Replace If the sensor tests faulty, replace it with a genuine Komatsu part (P/N 6732-81-3140 or equivalent). Clean all connector terminals with electrical contact cleaner and apply dielectric grease. Repair any damaged wiring using proper gauge wire and heat-shrink connectors. Clear the fault code using diagnostic software and perform a test run under load.

---

Disclaimer: This guide provides general diagnostic information. Always consult the official Komatsu PC800-7 service manual and consider professional assistance from certified Komatsu technicians for complex repairs. Improper diagnosis may lead to further equipment damage.