Sumitomo SH210-6 Fault Code 7248: Complete Diagnostic Guide

What is Sumitomo SH210-6 Fault Code 7248?

Fault Code 7248 on the Sumitomo SH210-6 excavator 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 specifically signals that the coolant temperature sensor is either sending erratic voltage signals, has experienced a complete circuit failure, or is registering temperatures outside the normal operating parameters.

This code is critical for the SH210-6 because the ECM relies on accurate coolant temperature data to manage fuel injection timing, engine protection protocols, and hydraulic oil temperature compensation. When this sensor fails, the engine may enter a protective derate mode to prevent overheating damage, significantly impacting jobsite productivity.

Common Symptoms

When Code 7248 is active on your Sumitomo SH210-6, operators typically experience:

• Engine warning light illuminated on the dashboard with possible audible alarm
• Reduced engine power or automatic derate limiting RPM to 1200-1500 range
• Erratic temperature gauge readings fluctuating between cold and hot extremes
• Difficulty starting when the engine is warm (ECM misreads temperature as cold)
• Excessive black smoke during operation due to incorrect fuel mapping

Potential Causes

For used Sumitomo SH210-6 excavators, the most common causes include:

• Faulty coolant temperature sensor (common failure point after 8,000+ operating hours)
• Corroded or damaged wiring harness connections near the thermostat housing
• Worn sensor connector pins allowing moisture intrusion (check the 2-pin Deutsch connector)
• ECM internal fault in the sensor input circuit (rare but possible on high-hour machines)
• Coolant contamination causing sensor element degradation
• Harness chafing against the engine block near the fuel filter bracket (known rub point on SH210-6 models)

How to Troubleshoot and Fix Code 7248

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor located on the engine block near the thermostat housing. Check the wiring harness for obvious damage, corrosion at the connector, or wear from rubbing against metal surfaces—a common issue on used excavators with 5,000+ hours.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance. At 68°F (20°C), resistance should read approximately 2,000-3,000 ohms. Test the harness voltage with ignition on—you should see approximately 5 volts from the ECM supply wire. Check for continuity to ground on the signal return wire.

Step 3: Component Replacement If sensor resistance is out of specification or the connector shows green corrosion (common in humid environments), replace the sensor with a genuine Sumitomo part. Always apply dielectric grease to connector pins on used machines to prevent future moisture issues. Clear codes using diagnostic software and verify proper operation.

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