What is Hitachi ZX200LC-5G Fault Code 11402-2?

Fault Code 11402-2 indicates a malfunction in the hydraulic pump solenoid valve circuit, specifically detecting an abnormal voltage or short circuit condition in the pump control system. This diagnostic trouble code (DTC) is generated by the engine control module (ECM) when it detects improper electrical signals from or to the hydraulic pump's proportional solenoid valve, which regulates pump displacement and flow based on operational demand.

This code is particularly critical for the ZX200LC-5G because the hydraulic pump solenoid directly controls the machine's load-sensing system. When this circuit malfunctions, the excavator cannot properly match hydraulic flow to work requirements, resulting in poor performance, excessive fuel consumption, and potential damage to the hydraulic system. On used machines, this fault often stems from age-related electrical degradation rather than mechanical pump failure.

Common Symptoms

• Reduced hydraulic power across all functions (boom, arm, bucket, and swing operations feel sluggish)
• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Erratic engine RPM as the ECM attempts to compensate for improper pump control signals
• Increased fuel consumption due to the pump operating at maximum displacement continuously
• Intermittent loss of hydraulic response, particularly during combined multi-function operations

Potential Causes

The most common causes for Code 11402-2 on used ZX200LC-5G excavators include:

• Damaged wiring harness near the hydraulic pump mounting area, where vibration and heat cause insulation breakdown and wire chafing
• Corroded or loose connector pins at the solenoid valve plug, especially on machines operating in wet or corrosive environments
• Failed proportional solenoid valve within the pump assembly due to internal coil breakdown or contamination
• ECM internal fault causing incorrect voltage output to the solenoid circuit
• Grounding issues where the harness ground point has corroded or loosened over time

How to Troubleshoot and Fix Code 11402-2

Step 1: Visual Inspection Begin by inspecting the wiring harness running from the ECM to the hydraulic pump solenoid. On used excavators, check for obvious damage, particularly where the harness passes near hot engine components or sharp metal edges. Examine the connector at the pump solenoid for corrosion, moisture intrusion, or bent pins.

Step 2: Electrical Testing Using a digital multimeter, disconnect the solenoid connector and measure resistance across the solenoid coil terminals. Typical specification is 10-15 ohms (consult your service manual). Then check for voltage supply from the ECM with the key on—you should see approximately 12V. Test for short circuits by measuring resistance between each solenoid wire and ground (should read infinite resistance).

Step 3: Connector and Ground Verification Clean all connector terminals with electrical contact cleaner and apply dielectric grease to prevent future corrosion. Verify the ground connection at the pump mounting bracket is clean, tight, and free of paint or corrosion—a common issue on older machines.

Step 4: Component Replacement If electrical tests confirm solenoid failure, replace the proportional solenoid valve. For used excavators, consider replacing the entire connector pigtail if wires show any signs of heat damage or brittleness, as this prevents recurring failures.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific serial number and seek assistance from qualified Hitachi technicians for complex diagnostics or repairs involving the ECM or hydraulic system.