What is Hitachi ZX360LC-5G Fault Code 13310-3?

Fault Code 13310-3 indicates a malfunction in the engine coolant temperature sensor circuit, specifically a voltage signal that is too high or out of normal operating range. This diagnostic trouble code (DTC) is generated when the Engine Control Module (ECM) detects an abnormal voltage reading from the coolant temperature sensor, typically exceeding 4.5 volts when normal operation should range between 0.5-4.0 volts.

This code is critical for the ZX360LC-5G because the coolant temperature sensor directly influences fuel injection timing, idle speed control, and engine protection protocols. When the ECM receives incorrect temperature data, it may default to a failsafe mode that limits machine performance or triggers engine derate to prevent potential damage. In Hitachi's Isuzu-powered excavators, accurate coolant temperature monitoring is essential for emissions control and optimal hydraulic system performance.

Common Symptoms

• Check Engine Light illuminated on the instrument panel with reduced engine power
• Engine running in cold-start mode continuously, causing rough idle and black smoke
• Hydraulic functions operating sluggishly due to ECM derate mode limiting engine RPM
• Engine cooling fan running constantly at maximum speed regardless of actual temperature
• Difficulty starting in cold weather or prolonged cranking before ignition

Potential Causes

The most common causes for Code 13310-3 on used ZX360LC-5G excavators include:

• Open circuit or broken wiring in the coolant temperature sensor harness, particularly where the wire bundle passes near the engine block mounting points (known wear point on this model)
• Failed coolant temperature sensor with internal resistance breakdown, common after 6,000+ operating hours
• Corroded or loose connector pins at the sensor plug, especially on machines operated in wet or marine environments
• Damaged ECM sensor ground circuit, causing voltage reference issues
• Chafed wiring insulation from contact with engine vibration dampeners or exhaust components

How to Troubleshoot and Fix Code 13310-3

Step 1: Visual Inspection Locate the coolant temperature sensor on the engine block (typically near the thermostat housing). Inspect the wiring harness for obvious damage, abrasion, or corrosion. On used excavators, carefully check where harnesses pass through metal brackets—this is a common failure point due to vibration wear.

Step 2: Electrical Testing Disconnect the sensor connector and use a digital multimeter to measure resistance across the sensor terminals. At 68°F (20°C), resistance should read approximately 2,000-3,000 ohms. Check connector pins for corrosion and clean with electrical contact cleaner. Measure voltage at the ECM harness side with ignition on—you should see approximately 5 volts reference voltage.

Step 3: Circuit Continuity Check Test continuity between the sensor connector and ECM pins (consult Hitachi service manual for specific pin locations). Resistance should be less than 5 ohms. Check the ground circuit integrity, as poor grounding is frequent on older machines with corroded chassis grounds.

Step 4: Component Replacement If sensor resistance is out of specification or wiring shows damage, replace the coolant temperature sensor with OEM or equivalent parts. For used excavators with high hours, consider replacing the entire sensor pigtail harness to prevent recurring issues.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Hitachi service manual and consider professional diagnostic services for complex electrical issues. Improper repairs may cause further damage or safety hazards.