Komatsu PC800SE-8R Fault Code E-13: Complete Diagnostic Guide

What is Komatsu PC800SE-8R Fault Code E-13?

Fault Code E-13 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 this sensor circuit fails or provides out-of-range values, the ECM triggers E-13 and may initiate protective measures.

Common Symptoms

When Code E-13 is active, operators typically experience:

• Engine overheat warning light illuminated on the monitor panel, even when coolant levels appear normal
• Reduced engine power (derate mode) limiting machine performance and hydraulic response
• Erratic temperature gauge readings that fluctuate abnormally or show maximum temperature immediately at startup
• Cooling fan running continuously at high speed regardless of actual engine temperature
• Difficulty starting or rough idle conditions, particularly in cold weather

Potential Causes

The most common technical causes for E-13 on used PC800SE-8R excavators include:

• Faulty coolant temperature sensor due to internal element degradation (common after 8,000+ operating hours)
• Corroded or loose connector pins at the sensor harness connection point near the thermostat housing
• Damaged wiring harness from rubbing against engine components, particularly where the harness routes along the cylinder head
• Low coolant level or air pockets in the cooling system causing inaccurate readings
• ECM internal fault or corrupted calibration data (less common but possible in high-hour machines)
• Aftermarket sensor installation with incorrect resistance specifications

How to Troubleshoot and Fix Code E-13

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) and its wiring harness for physical damage, corrosion, or oil contamination. On used excavators, pay special attention to connector terminals—clean with electrical contact cleaner if corrosion is present.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure its resistance. At 68°F (20°C), resistance should read approximately 2,000-3,000 ohms (consult service manual for exact specifications). Check harness continuity from sensor connector to ECM pins—resistance should be less than 5 ohms. Inspect for short circuits to ground (should read infinite resistance).

Step 3: Sensor Replacement and System Verification If readings are out of specification, replace the coolant temperature sensor with a genuine Komatsu part (P/N 6732-81-3140 or equivalent). After installation, bleed the cooling system to remove air pockets. Clear the fault code using Komatsu diagnostic software (KOMTRAX) or a compatible scan tool, then run the engine through temperature cycles to verify proper operation.

For used machinery, always inspect harness routing for wear points where cables contact engine components—use protective loom or reroute if necessary before finalizing repairs.

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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.