Sumitomo SH210LC-5LR Fault Code 7602: Complete Diagnostic Guide

What is Sumitomo SH210LC-5LR Fault Code 7602?

Fault Code 7602 indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the ECM (Engine Control Module). This diagnostic trouble code (DTC) is triggered when the coolant temperature sensor sends voltage signals outside the manufacturer's specified range, or when the sensor circuit experiences an open or short condition.

This code is critical for the SH210LC-5LR because the ECM relies on accurate coolant temperature data to control fuel injection timing, engine protection protocols, and hydraulic oil temperature management. Ignoring this fault can lead to engine overheating, reduced hydraulic performance, or catastrophic engine damage on used machines with aging cooling systems.

Common Symptoms

When Code 7602 is active, operators typically experience:

• Check engine light or warning lamp illuminated on the instrument panel
• Engine derate mode activated, limiting power output and hydraulic flow to protect components
• Erratic temperature gauge readings or gauge stuck at minimum/maximum positions
• Cooling fan running continuously at high speed, even during cold starts
• Hard starting or rough idling when the engine is cold, as the ECM receives incorrect temperature data

Potential Causes

The most common technical reasons for Code 7602 on used SH210LC-5LR excavators include:

• Faulty coolant temperature sensor (CTS) due to internal resistance drift or element failure after years of thermal cycling
• Corroded or loose wiring connections at the sensor harness connector, especially common in machines operated in wet or marine environments
• Damaged sensor wiring harness, particularly at rub points near the engine block or where harnesses route over vibrating components
• ECM internal fault affecting the temperature sensor input circuit (less common but possible in high-hour machines)
• Contaminated coolant causing sensor element coating or degradation
• Incorrect sensor installation or aftermarket sensor incompatibility on previously repaired machines

How to Troubleshoot and Fix Code 7602

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, or corrosion on the sensor body and electrical connector. On used excavators, carefully examine the wiring harness for chafing, especially where it contacts frame members or routing clips.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure sensor resistance. At 68°F (20°C), resistance should typically read 2,000-3,000 ohms (consult service manual for exact specifications). Test for circuit continuity between the sensor connector and ECM pins, checking for open circuits. Measure voltage supply at the harness connector with ignition on—you should see approximately 5 volts reference voltage from the ECM.

Step 3: Component Replacement and Verification If resistance values are out of specification or wiring shows damage, replace the faulty component. For used machines, always apply dielectric grease to connector terminals to prevent future corrosion. After repairs, clear the fault code using Sumitomo diagnostic software or a compatible scan tool, then monitor coolant temperature readings during a complete warm-up cycle to verify proper operation.

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