What is Hitachi ZX210LCK-5G Fault Code 14106-2?

Fault Code 14106-2 on the Hitachi ZX210LCK-5G excavator indicates a low voltage condition in the Engine Speed Sensor (Revolution Sensor) Circuit. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects voltage levels below the manufacturer's specified threshold in the sensor circuit responsible for monitoring engine RPM.

The engine speed sensor is critical for proper fuel injection timing, governor control, and overall engine performance. When this circuit fails on the ZX210LCK-5G's Isuzu engine, the ECM cannot accurately determine engine speed, leading to improper fuel delivery and potential operational hazards. This code directly affects machine productivity and can cause unexpected shutdowns.

Common Symptoms

When fault code 14106-2 is active, operators typically experience:

• Engine warning light illuminated on the instrument cluster or continuous beeping alarm
• Erratic engine RPM readings on the dashboard, showing zero or fluctuating values despite engine running
• Loss of power or engine derating to protect components from potential damage
• Rough idling or unstable engine operation, particularly noticeable at low RPM
• Difficulty starting the machine or unexpected engine stalling during operation

Potential Causes

The most common technical reasons for this fault code on used ZX210LCK-5G excavators include:

• Damaged or corroded wiring harness near the engine speed sensor, especially at common rub points along the engine block where vibration causes insulation wear
• Faulty engine speed sensor itself, which degrades over time due to heat exposure and contamination from oil leaks
• Poor electrical connections at the sensor connector, often caused by moisture intrusion or corrosion on terminals
• Broken or frayed wires in the sensor circuit between the sensor and ECM, particularly in the engine bay routing
• Low battery voltage or charging system issues affecting overall electrical system performance
• ECM internal faults (less common), where the control module's sensor circuit driver has failed

How to Troubleshoot and Fix Code 14106-2

Step 1: Visual Inspection Begin by locating the engine speed sensor on the flywheel housing of the Isuzu engine. Inspect the wiring harness for obvious damage, chafing, or oil contamination. Check connector pins for corrosion, bent terminals, or moisture. On used excavators, pay special attention to harness routing near heat sources and moving components where insulation commonly deteriorates.

Step 2: Electrical Testing Using a digital multimeter, check the sensor's resistance. With the sensor disconnected, measure between the sensor terminals—typical resistance should be 150-300 ohms (consult your service manual for exact specifications). Next, measure voltage at the ECM connector with the key on, engine off. You should see approximately 5 volts reference voltage from the ECM.

Step 3: Circuit Continuity Check Test continuity between the sensor connector and ECM pins to verify no open circuits exist. Check for shorts to ground by measuring resistance between each circuit wire and chassis ground with the harness disconnected—readings should show infinite resistance (open circuit).

Step 4: Signal Testing Reconnect everything and use Hitachi Dr.EX diagnostic software or compatible scan tool to monitor live engine speed sensor data while cranking. The signal should show voltage fluctuation (typically 0-5V AC signal) as the engine turns. No signal change indicates sensor failure.

Step 5: Repair or Replace If wiring issues are found, repair damaged sections using proper gauge wire and weatherproof connectors. For corroded connections on used machines, clean terminals with electrical contact cleaner and apply dielectric grease. Replace the sensor if internal resistance is out of specification. After repairs, clear codes and perform a test run under load.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific machine serial number and seek assistance from certified Hitachi technicians for complex electrical diagnostics or if you're uncertain about any procedure.