What is Hitachi ZX200-5G-HCMC Fault Code 14106-2?

Fault Code 14106-2 indicates a hydraulic pump displacement sensor circuit malfunction, specifically a voltage signal deviation or intermittent connection in the main pump control system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal voltage reading from the pump displacement feedback sensor, which monitors the swash plate angle of the variable displacement hydraulic pump.

This code is critical for the ZX200-5G-HCMC because the hydraulic pump displacement sensor directly controls engine-pump matching, ensuring optimal fuel efficiency and hydraulic performance. When this sensor circuit fails, the ECM cannot properly regulate pump output, leading to reduced machine productivity and potential over-revving conditions that can damage both the engine and hydraulic components.

Common Symptoms

• Reduced hydraulic power across all functions, with noticeably slower boom, arm, and bucket movements
• Engine over-revving without corresponding increase in hydraulic performance (poor engine-pump matching)
• Intermittent service warning light on the instrument panel, sometimes clearing after machine restart
• Erratic hydraulic response where attachment speeds fluctuate unpredictably during operation
• Increased fuel consumption due to inefficient pump control and constant high-RPM operation

Potential Causes

The most common technical causes for Code 14106-2 on used ZX200-5G excavators include:

• Corroded or loose connector pins at the pump displacement sensor (located on the main hydraulic pump housing), especially common in machines operating in wet or coastal environments
• Damaged wiring harness between the sensor and ECM, particularly at known rub points near the pump mounting bracket and along the right-side frame rail
• Failed pump displacement sensor itself, with internal potentiometer wear causing inconsistent voltage output (typically should read 0.5-4.5V DC)
• ECM ground circuit issues or corroded ground connections affecting sensor reference voltage
• Contamination or hydraulic oil intrusion into the sensor connector, common in high-hour used machines with deteriorated seals

How to Troubleshoot and Fix Code 14106-2

Step 1: Visual Inspection and Connector Check Begin by inspecting the pump displacement sensor connector located on the main hydraulic pump. Disconnect the 3-pin connector and examine for corrosion, bent pins, or hydraulic oil contamination. Clean contacts with electrical contact cleaner and check for physical damage to the wiring harness along its route to the ECM.

Step 2: Voltage and Resistance Testing Using a digital multimeter, check the sensor supply voltage with the key on, engine off. You should read approximately 5 volts DC at the supply wire (typically red/white). Check sensor ground continuity (should be less than 1 ohm resistance to chassis ground). With the sensor disconnected, measure sensor internal resistance between signal and ground pins—normal range is 500-4,500 ohms depending on swash plate position.

Step 3: Dynamic Signal Testing Connect Hitachi Dr.EX diagnostic software or compatible scan tool to monitor live sensor voltage while manually moving the pump control lever. Voltage should change smoothly from approximately 0.5V to 4.5V without dropouts or spikes. Erratic readings confirm sensor replacement is needed (Hitachi part number varies by serial number—verify before ordering).

Step 4: Harness and Ground Verification For used excavators, thoroughly inspect the engine-to-frame ground straps and ECM ground connections, as corrosion here commonly causes sensor circuit issues. Check for harness chafing at the swivel joint and along the pump mounting area where vibration causes wire insulation breakdown.

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. Improper repairs may cause further damage or safety hazards.