What is Hitachi ZX470LCH-5G Fault Code 14106-2?

Fault Code 14106-2 indicates a malfunction in the Engine Speed Sensor Circuit - specifically an intermittent or erratic signal condition. This code triggers when the Electronic Control Module (ECM) detects inconsistent voltage patterns or irregular pulse signals from the crankshaft position sensor, which is critical for proper engine timing and fuel injection control.

On the Hitachi ZX470LCH-5G excavator, this sensor directly affects the Isuzu engine's ability to maintain accurate RPM readings and synchronize fuel delivery. When this circuit fails, the ECM cannot properly calculate engine position, leading to performance degradation or complete shutdown in severe cases. This is particularly critical for the ZX470LCH-5G's common rail fuel injection system, which requires precise timing data to optimize combustion and meet emissions standards.

Common Symptoms

• Engine warning light illuminated on the instrument cluster with possible derate mode activation
• Rough idling or inconsistent engine RPM, especially noticeable during warm-up or under load
• Intermittent stalling or difficulty restarting after the machine reaches operating temperature
• Loss of power during digging operations as the ECM enters limp mode to protect the engine
• Black smoke from the exhaust due to improper fuel injection timing

Potential Causes

The most common causes for Code 14106-2 on used ZX470LCH-5G excavators include:

• Corroded or damaged sensor connectors - particularly common on machines with 5,000+ operating hours where moisture infiltrates the sealed connections
• Worn crankshaft position sensor with internal winding failures causing intermittent signal loss
• Damaged wiring harness near the engine mounting points where vibration causes wire insulation breakdown and shorts
• Air gap issues between the sensor and crankshaft reluctor ring due to mounting bracket wear or sensor positioning
• ECM internal faults in older machines, though less common than sensor-circuit issues
• Contaminated sensor face from oil leaks or metallic debris affecting magnetic field readings

How to Troubleshoot and Fix Code 14106-2

Step 1: Visual Inspection and Connector Check Begin by locating the engine speed sensor on the lower left side of the engine block near the flywheel housing. Disconnect the sensor connector and inspect for corrosion, bent pins, or oil contamination. On used excavators, check for harness rubbing against the engine block or frame rails - a known wear point on this model.

Step 2: Sensor Resistance Testing Using a digital multimeter, measure the sensor's internal resistance across its two pins. The reading should typically be between 190-250 ohms at room temperature. Any reading outside this range indicates sensor replacement is necessary. Also check for continuity to ground - there should be infinite resistance (open circuit).

Step 3: Wiring Harness Continuity Test Test the wiring harness from the sensor connector back to the ECM. Check for proper continuity on both signal wires and verify there's no short to ground or to each other. Pay special attention to areas where the harness passes through metal grommets or near hot exhaust components.

Step 4: Air Gap Verification If resistance values are correct, verify the air gap between the sensor tip and the crankshaft reluctor ring. The gap should be 0.5-1.5mm. Use feeler gauges to confirm proper spacing. Excessive gap from worn mounting or sensor backing-out is common in high-hour machines.

Step 5: Clear Code and Test After repairs, use Hitachi Dr.EX diagnostic software or equivalent scan tool to clear the fault code. Run the engine through various RPM ranges while monitoring live data for consistent sensor signal. For used equipment, perform this test under load conditions to replicate real operating scenarios.

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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, especially when working with high-hour used equipment.