What is Hitachi ZX470LCH-5G Fault Code 13310-3?

Fault Code 13310-3 indicates a malfunction in the engine coolant temperature sensor circuit, specifically detecting an intermittent or out-of-range signal from the coolant temperature sensor to the Engine Control Module (ECM). This diagnostic trouble code (DTC) means the ECM is receiving erratic voltage readings that fall outside the manufacturer's specified parameters for normal coolant temperature monitoring.

In the Hitachi ZX470LCH-5G excavator, this code directly affects the Isuzu engine's ability to properly manage fuel injection timing, idle speed, and emissions controls. The ECM relies on accurate coolant temperature data to optimize engine performance across varying operating conditions. When this sensor circuit fails, the engine may default to safe-mode parameters that reduce efficiency and power output, making this a critical issue for productivity on job sites.

Common Symptoms

• Check Engine Light illuminated on the instrument cluster with possible derate warning
• Engine runs rough during cold starts or fails to reach proper operating temperature
• Excessive black smoke from exhaust due to improper fuel-air mixture calculations
• Cooling fan runs continuously at high speed regardless of actual engine temperature
• Reduced hydraulic performance or power loss as ECM enters protective mode

Potential Causes

The most common causes for Code 13310-3 on used ZX470LCH-5G excavators include:

• Corroded or loose connector at the coolant temperature sensor (CTS) located near the thermostat housing
• Damaged wiring harness between sensor and ECM, particularly at known rub points along the engine block
• Failed coolant temperature sensor itself, common in machines with 5,000+ operating hours
• Water intrusion into sensor connector causing intermittent short circuits
• ECM ground circuit degradation due to corrosion on aging machines
• Incorrect coolant mixture leading to sensor element deterioration

How to Troubleshoot and Fix Code 13310-3

Step 1: Visual Inspection Begin by locating the coolant temperature sensor on the engine block (typically near the thermostat housing on Isuzu engines). Inspect the connector for corrosion, moisture, or damaged pins. Check the wiring harness for chafing, especially where it contacts the engine block or frame—a common wear point on used excavators.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor connector and measure resistance across the sensor terminals. At room temperature (68°F/20°C), resistance should read approximately 2,000-3,000 ohms. Compare readings against Hitachi's specifications. Test the harness voltage at the ECM connector; you should see approximately 5 volts reference voltage with key on, engine off.

Step 3: Signal Testing Reconnect the sensor and use Hitachi Dr.EX diagnostic software or compatible scan tool to monitor live coolant temperature data. Compare displayed temperature against actual engine temperature using an infrared thermometer. Erratic readings or values that don't correlate with actual temperature confirm sensor or circuit failure.

Step 4: Repair or Replace For used excavators, clean all connectors with electrical contact cleaner and apply dielectric grease before reinstalling. Replace damaged wiring harness sections using heat-shrink connections rated for engine compartment temperatures. If sensor testing fails specifications, replace with genuine Hitachi/Isuzu parts to ensure proper ECM communication.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific serial number and consider professional diagnostic assistance for complex electrical issues.