What is Hitachi ZX200-5G-HCMC Fault Code 14107-2?

Fault Code 14107-2 indicates a malfunction in the DEF (Diesel Exhaust Fluid) pressure sensor circuit, specifically detecting an abnormal voltage signal or intermittent connection within the SCR (Selective Catalytic Reduction) system. This code is part of Hitachi's emission control diagnostic framework and directly affects the excavator's ability to meet Tier 4 Final emission standards.

The DEF pressure sensor monitors the pressure of diesel exhaust fluid being injected into the exhaust stream to reduce NOx emissions. When the ECM (Engine Control Module) detects voltage readings outside the expected range (typically 0.5-4.5V), it triggers this fault code. For the ZX200-5G-HCMC model, this system is critical because prolonged malfunction can result in engine derate or prevent the machine from starting after shutdown, significantly impacting jobsite productivity.

Common Symptoms

• Amber or red emission warning light illuminated on the instrument cluster
• Engine power derate (typically 25-40% reduction) after extended operation with active fault
• DEF system malfunction message displayed on the monitor panel
• Rough idle or hesitation during load application due to ECM compensating for emission system errors
• Inability to regenerate DPF (Diesel Particulate Filter) properly, leading to secondary fault codes

Potential Causes

The most common technical causes for Code 14107-2 on used Hitachi excavators include:

• Corroded or damaged wiring harness at the DEF tank mounting area, where vibration and moisture exposure cause connector degradation
• Failed DEF pressure sensor due to crystallized urea buildup or internal sensor element failure (common after 4,000-6,000 operating hours)
• Intermittent connection at the 6-pin connector near the DEF tank, a known wear point on ZX200-5G models
• Low DEF fluid quality or contaminated fluid causing sensor membrane coating and inaccurate readings
• ECM software version requiring update to address known sensor calibration issues in early production units
• Damaged DEF supply lines creating actual pressure anomalies that trigger sensor fault detection

How to Troubleshoot and Fix Code 14107-2

Step 1: Visual Inspection and Connector Check Begin by inspecting the DEF pressure sensor located on the DEF tank assembly. Check the wiring harness for abrasion points where it contacts the frame rail (common rub point on this model). Disconnect the sensor connector and inspect pins for corrosion, bent terminals, or moisture intrusion. Clean contacts with electrical contact cleaner and dielectric grease.

Step 2: Sensor Voltage Testing Using a digital multimeter, backprobe the sensor connector with the ignition on. Measure the supply voltage (should read 4.8-5.2V on the reference wire) and ground continuity (less than 0.5 ohms resistance). With the sensor connected, measure the signal wire voltage at idle—it should fluctuate between 0.8-3.2V depending on DEF pressure.

Step 3: DEF Quality and Physical Inspection Drain a DEF sample and check for contamination or crystallization. On used excavators, old or degraded DEF is a frequent culprit. Inspect the DEF lines and injector for blockages. Use Dr.EX diagnostic software (Hitachi's proprietary tool) to perform active tests, commanding the DEF pump to verify actual pressure versus sensor readings.

Step 4: Component Replacement and Calibration If voltage tests confirm sensor failure, replace with a genuine Hitachi DEF pressure sensor (Part# 4679981 or equivalent). After replacement, clear codes using diagnostic software and perform a SCR system recalibration. For used machines, always replace the sensor connector pigtail simultaneously to prevent recurring issues from worn terminals.

Professional Disclaimer: While this guide provides technical troubleshooting steps, emission system repairs may require certified diagnostic equipment and software. Consult a qualified Hitachi technician or authorized service center for complex ECM programming or if fault codes persist after component replacement.