What is Hitachi ZX870LC-5A Fault Code 13311-3?

Fault Code 13311-3 on the Hitachi ZX870LC-5A indicates a malfunction in the engine coolant temperature sensor circuit, specifically a voltage signal that is out of the expected range or intermittent connectivity. This code is triggered when the Engine Control Module (ECM) detects abnormal electrical values from the coolant temperature sensor, which monitors the operating temperature of the Isuzu engine powering this large excavator.

This fault is critical because the ECM relies on accurate coolant temperature data to optimize fuel injection timing, control engine warm-up cycles, and prevent overheating. On a machine as large as the ZX870LC-5A, incorrect temperature readings can lead to poor fuel economy, increased emissions, and potential engine damage if the cooling system isn't functioning properly.

Common Symptoms

When fault code 13311-3 is active, operators may experience:

• Check Engine light or warning lamp illuminated on the instrument panel
• Engine running in limp mode or derate, reducing available power and hydraulic performance
• Difficulty starting in cold conditions, or excessive white smoke during warm-up
• Cooling fan running continuously at high speed, even when engine is cold
• Inaccurate temperature gauge readings or erratic needle movement on the dashboard

Potential Causes

The most common technical causes for this fault code on used ZX870LC-5A excavators include:

• Faulty coolant temperature sensor due to internal resistance breakdown (common after 5,000+ operating hours)
• Damaged wiring harness or connector corrosion near the sensor, particularly where the harness routes along the engine block and experiences heat cycling
• Broken or frayed wires at known rub points between the engine and chassis frame
• Poor ground connection at the sensor or ECM harness grounds
• ECM internal fault (rare, but possible in high-hour machines)
• Coolant contamination causing sensor element fouling

How to Troubleshoot and Fix Code 13311-3

Step 1: Visual Inspection Begin by inspecting the coolant temperature sensor and its wiring harness for obvious damage. On used excavators, check for wire insulation wear where the harness contacts the engine block, corrosion on the sensor connector pins, and coolant leaks near the sensor mounting location.

Step 2: Electrical Testing Using a digital multimeter, measure the sensor's resistance. At room temperature (20°C/68°F), resistance should typically read between 2,000-3,000 ohms (consult Hitachi service manual for exact specs). Check for voltage supply at the sensor connector—you should see approximately 5 volts from the ECM with the key on, engine off.

Step 3: Harness Continuity Check Disconnect both ends of the sensor harness and test for continuity between the sensor connector and ECM pins. Also check for shorts to ground or other circuits. Pay special attention to areas where harnesses pass through grommets or near hot exhaust components.

Step 4: Sensor Replacement and Verification If testing reveals sensor failure, replace with a genuine Hitachi or OEM-equivalent coolant temperature sensor. After installation, clear the fault code using Hitachi Dr.EX diagnostic software or a compatible scan tool, then run the engine through a complete heat cycle to verify the repair.

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