What is Sumitomo SH210LC-5LR Fault Code 341?

Fault Code 341 on the Sumitomo SH210LC-5LR indicates a malfunction in the hydraulic oil temperature sensor circuit, specifically detecting an abnormal voltage signal or open circuit condition. This code is triggered when the ECM (Engine Control Module) receives voltage readings outside the expected range from the temperature sensor monitoring hydraulic oil temperature in the main hydraulic system.

This fault is critical for the SH210LC-5LR because hydraulic oil temperature directly affects system efficiency, component longevity, and operational safety. The excavator's control system relies on accurate temperature data to prevent overheating, adjust pump output, and protect seals and hoses from thermal damage. When this sensor circuit fails, the ECM cannot properly regulate hydraulic system performance, potentially leading to accelerated wear or catastrophic component failure.

Common Symptoms

• Hydraulic oil temperature warning light illuminated on the instrument panel, often accompanied by an audible alarm
• Reduced hydraulic performance including slower cycle times and decreased digging force as the system enters protective derate mode
• Erratic temperature gauge readings showing abnormally high, low, or fluctuating values that don't match actual operating conditions
• ECM fault code storage with possible activation of backup temperature values, causing the machine to operate as if oil temperature is at a default setting
• Intermittent code triggering particularly noticeable during machine startup or when operating in extreme ambient temperatures

Potential Causes

The most common causes of Code 341 on used SH210LC-5LR excavators include:

• Damaged or corroded sensor connector at the hydraulic tank, especially where the harness routes near the swing bearing (a known rub point on this model)
• Failed hydraulic oil temperature sensor due to age-related internal resistance drift or moisture intrusion in the sensor body
• Broken or chafed wiring in the sensor harness between the hydraulic tank and the main wiring bundle near the cab mount
• Corroded pins or moisture in the ECM connector, particularly on machines operated in high-humidity or marine environments
• Poor ground connection at the sensor mounting point caused by rust, paint, or thread sealant contamination
• ECM internal fault (rare) affecting the temperature sensor input circuit

How to Troubleshoot and Fix Code 341

Step 1: Visual Inspection Begin by locating the hydraulic oil temperature sensor mounted in the hydraulic tank (typically on the left side of the machine). Inspect the sensor connector for corrosion, bent pins, or moisture. On used excavators, carefully trace the wiring harness checking for rub points against the swing bearing housing, frame edges, or hydraulic lines where insulation may be worn through.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure sensor resistance. At room temperature (20°C/68°F), resistance should typically read 2,000-3,000 ohms (consult your service manual for exact specifications). Check for continuity in the wiring harness from the sensor connector back to the ECM connector. Measure voltage supply at the sensor connector with the ignition on—you should see approximately 5 volts reference voltage from the ECM.

Step 3: Component Testing and Replacement If resistance values are out of specification or the sensor shows an open circuit, replace the temperature sensor using a genuine Sumitomo part. Before installation, clean the mounting threads and ensure proper ground contact. If wiring shows damage, repair using weatherproof heat-shrink connectors and secure the harness away from moving components. Clear the fault code using Sumitomo diagnostic software or a compatible scan tool, then operate the machine through a complete warm-up cycle to verify the repair.

Critical for Used Equipment: Always apply dielectric grease to connectors during reassembly and consider replacing the entire sensor harness if the machine has over 8,000 operating hours, as internal wire degradation often causes intermittent faults that are difficult to diagnose.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual for your specific machine serial number and seek qualified professional assistance for complex electrical diagnostics or repairs.