What is Hitachi ZX210K-5G Fault Code 14105-2?

Fault Code 14105-2 on the Hitachi ZX210K-5G indicates a malfunction in the engine oil pressure sensor circuit, specifically a signal voltage that is too low or an open circuit condition. This code is triggered when the Engine Control Module (ECM) detects that the oil pressure sensor is sending an abnormally low voltage signal or no signal at all, typically below 0.5 volts when the engine is running.

This fault is critical for the ZX210K-5G because the oil pressure monitoring system directly protects the Isuzu engine from catastrophic damage. When the ECM cannot accurately read oil pressure data, it may initiate engine derate modes or shutdown protocols to prevent bearing failure and internal engine damage. For used excavators, this code often appears due to sensor deterioration or wiring issues rather than actual oil pressure problems.

Common Symptoms

• Oil pressure warning light illuminated continuously on the instrument cluster, even when engine oil pressure is normal
• Engine derate mode activated, limiting maximum RPM to approximately 1,500-1,800 RPM to protect the engine
• ECM error code displayed on the monitor panel, preventing normal operation until resolved
• Intermittent loss of power or unexpected engine shutdown during operation, particularly during high-load conditions
• Abnormal engine sounds or hesitation during startup due to protective protocols engaging

Potential Causes

The most common technical causes for Code 14105-2 on used ZX210K-5G excavators include:

• Failed oil pressure sensor due to internal electrical component degradation (common after 5,000+ operating hours)
• Damaged wiring harness between the sensor and ECM, particularly at known rub points near the engine mount brackets and along the valve cover
• Corroded or loose electrical connectors at the sensor terminal or ECM connection points, especially in machines exposed to water or moisture
• Broken signal wire within the harness insulation, often caused by vibration and flexing over time
• ECM internal circuit failure (rare, but possible in high-hour used machines with electrical system stress)

How to Troubleshoot and Fix Code 14105-2

Step 1: Visual Inspection and Connector Check Begin by locating the oil pressure sensor on the engine block (typically near the oil filter housing on Isuzu engines). Inspect the electrical connector for corrosion, bent pins, or moisture intrusion. On used excavators, clean all connector terminals with electrical contact cleaner and apply dielectric grease to prevent future corrosion.

Step 2: Sensor Signal Testing Using a digital multimeter, backprobe the sensor signal wire with the ignition on and engine running. The voltage should read between 0.5-4.5 volts depending on oil pressure. If the reading is below 0.3 volts or shows no continuity, disconnect the sensor and test the harness continuity from the sensor connector to the ECM. Check for resistance values between 50-150 ohms on the signal circuit.

Step 3: Sensor Replacement and Harness Repair If the sensor tests faulty (common failure point), replace it with a genuine Hitachi/Isuzu oil pressure sensor (Part# 8-97328-047-1 or equivalent). Before installation, inspect the wiring harness along known wear points—particularly where it contacts the engine block or frame rails. Repair any damaged insulation with heat-shrink tubing and secure harnesses away from moving components. For used machines, consider replacing the entire sensor-to-ECM harness section if multiple repairs have been made previously.

Step 4: Clear Codes and Verify After repairs, use Hitachi Dr.EX diagnostic software or compatible scan tool to clear the fault code. Run the engine through various load conditions and monitor for code recurrence. Verify actual oil pressure with a mechanical gauge to ensure readings match ECM data.

---

Disclaimer: This guide provides general diagnostic information for Code 14105-2. 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 if you're unfamiliar with high-voltage systems.