Komatsu PC750SE-7 Fault Code E213: Complete Diagnostic Guide

What is Komatsu PC750SE-7 Fault Code E213?

Fault Code E213 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 sensor sending irregular voltage signals or detecting temperatures outside the normal operating parameters for the Komatsu SAA6D140E-7 engine.

This fault is critical because the ECM relies on accurate coolant temperature data to optimize fuel injection timing, control engine protection systems, and manage the cooling fan operation. When E213 triggers, the engine may enter a protective derate mode to prevent overheating damage, significantly impacting machine productivity and potentially causing costly engine repairs if ignored.

Common Symptoms

When Code E213 is active on your PC750SE-7, operators typically experience:

• Engine warning light illuminated on the monitor panel with reduced engine power
• Automatic engine derate or speed limitation, preventing full throttle operation
• Cooling fan running continuously at high speed, even during cold starts
• Difficulty starting the engine or extended cranking times in cold conditions
• Erratic temperature gauge readings or temperature display showing abnormal values (extremely high or low)

Potential Causes

The most common technical reasons for E213 on used PC750SE-7 excavators include:

• Coolant temperature sensor failure due to age-related degradation or internal element breakdown
• Damaged wiring harness between the sensor and ECM, particularly at rub points near the engine block or frame rails
• Corroded or loose electrical connectors at the sensor plug, common in machines with high hour counts or exposure to harsh environments
• ECM internal fault affecting the temperature sensor circuit processing
• Actual engine overheating condition triggering legitimate high-temperature warnings
• Coolant system issues including low coolant level, air pockets, or thermostat failure causing genuine temperature anomalies

How to Troubleshoot and Fix Code E213

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the engine block (typically near the thermostat housing). Check for physical damage, coolant leaks around the sensor, and examine the wiring harness for chafing, cuts, or heat damage. On used excavators, pay special attention to harness routing where it contacts metal surfaces.

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 2,000-3,000 ohms (consult your service manual for exact specifications). Test harness continuity from the sensor connector back to the ECM, checking for opens or shorts to ground.

Step 3: Connector and Ground Verification Clean all connector pins with electrical contact cleaner and inspect for corrosion—a frequent issue in older machines. Verify the sensor ground circuit has less than 0.5 ohms resistance to chassis ground. Corroded grounds are particularly common on high-hour PC750SE-7 units.

Step 4: Sensor Replacement and System Reset If testing confirms sensor failure, replace with a genuine Komatsu coolant temperature sensor (Part #6754-81-6210 or equivalent). After replacement, clear the fault code using Komatsu diagnostic software (KOMTRAX) or a compatible scan tool, then monitor for code recurrence during operation.

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