Komatsu PC360-8M0 Fault Code E-35: Complete Diagnostic Guide

What is Komatsu PC360-8M0 Fault Code E-35?

Fault Code E-35 on the Komatsu PC360-8M0 indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Engine Control Module (ECM).

This diagnostic trouble code specifically relates to the coolant temperature sensor system, which monitors engine operating temperature and sends critical data to the ECM. The ECM uses this information to regulate fuel injection timing, idle speed, and activate cooling fan operation. For the PC360-8M0's Komatsu SAA6D114E engine, maintaining accurate temperature monitoring is essential to prevent overheating, optimize fuel efficiency, and protect internal engine components from thermal damage. When E-35 triggers, the ECM may default to a predetermined temperature value, potentially causing suboptimal engine performance.

Common Symptoms

When Code E-35 is active on your PC360-8M0, operators typically experience:

• Engine warning light illuminated on the monitor panel with E-35 displayed
• Hard starting or extended cranking time, especially in cold conditions
• Excessive black smoke from exhaust due to improper fuel mixture calculations
• Cooling fan running continuously at high speed, even when engine is cold
• Engine derate mode activation, limiting maximum RPM and hydraulic performance to protect the engine

Potential Causes

The most common technical reasons for E-35 on used PC360-8M0 excavators include:

• Faulty coolant temperature sensor due to internal element degradation (common after 5,000+ operating hours)
• Damaged or corroded wiring harness at connector points, particularly where the harness routes near the engine block
• Broken or frayed sensor wires caused by vibration and heat cycling in the engine compartment
• Corroded connector pins at the sensor or ECM connection points due to coolant leaks or moisture intrusion
• ECM internal fault (rare, but possible in high-hour machines)
• Low coolant level causing sensor exposure and erratic readings

How to Troubleshoot and Fix Code E-35

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the engine block (typically near the thermostat housing on the SAA6D114E engine). Check for physical damage, coolant leaks around the sensor base, and verify adequate coolant level. On used excavators, examine the wiring harness for signs of rubbing, heat damage, or oil contamination along its entire length to the ECM.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Test harness continuity from sensor connector to ECM pins, checking for opens or shorts to ground. Inspect connector pins for corrosion or bent terminals—a frequent issue in older machines.

Step 3: Live Data Analysis Connect Komatsu diagnostic software (KOMTRAX or compatible scan tool) to monitor real-time coolant temperature readings. Compare sensor output voltage (typically 0.5-4.5V range) against actual engine temperature using an infrared thermometer. If readings differ significantly or sensor shows implausible values (below -40°F or above 300°F), replace the sensor.

Step 4: Component Replacement Replace the coolant temperature sensor using OEM or quality aftermarket parts, applying thread sealant as specified. Clear fault codes and perform a test cycle. If the code returns, inspect ECM grounds and consider ECM evaluation.

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Disclaimer: This guide provides general diagnostic information. Always consult your Komatsu service manual and consider professional assistance for complex electrical diagnostics, especially on used equipment with unknown service history.