What is Hitachi ZX690LCH-5A Fault Code 14106-2?

Fault Code 14106-2 indicates a communication error or abnormal signal between the Engine Control Module (ECM) and the Hydraulic Pump Control System, specifically related to pump flow control solenoid circuit malfunction. This diagnostic trouble code (DTC) is triggered when the ECM detects an electrical irregularity—such as an open circuit, short to ground, or voltage deviation—in the proportional solenoid valve that regulates main hydraulic pump displacement.

For the ZX690LCH-5A, this is particularly critical because this large excavator relies on precise pump control to balance engine load with hydraulic demand. When communication fails between the ECM and pump solenoid, the machine may enter a derate mode to prevent engine overload or hydraulic system damage, significantly impacting productivity on job sites.

Common Symptoms

• Yellow engine warning light illuminated on the monitor panel with reduced engine power output
• Noticeable loss of hydraulic power during combined operations (swing + boom movements)
• Machine entering limp mode with restricted travel speed and reduced cycle times
• Intermittent or complete loss of automatic engine speed control matching hydraulic load
• Abnormal engine hunting or surging at idle due to improper pump load feedback

Potential Causes

The most common technical failures triggering Code 14106-2 on used ZX690LCH-5A excavators include:

• Faulty pump control solenoid valve with internal coil degradation or contaminated spool (common after 6,000+ operating hours)
• Damaged wiring harness between ECM and pump solenoid, particularly at routing points near the pump mounting area where vibration causes wire chafing
• Corroded or moisture-contaminated connector terminals at the solenoid plug (check the 3-pin Deutsch connector)
• ECM internal circuit failure on the pump control output driver (less common but occurs in high-hour machines)
• Voltage supply issues from the main power relay affecting solenoid energization (check for 24V DC supply)

How to Troubleshoot and Fix Code 14106-2

Step 1: Visual Inspection and Connector Check Begin by inspecting the pump control solenoid connector located on the main hydraulic pump. Disconnect the 3-pin connector and examine terminals for corrosion, bent pins, or moisture intrusion. Clean contacts with electrical contact cleaner and apply dielectric grease. On used excavators, this routing area is prone to hydraulic oil contamination.

Step 2: Electrical Testing with Multimeter With ignition off, measure solenoid coil resistance across terminals. Specification should be 10-15 ohms at 20°C. Next, check for voltage supply with ignition on: you should read approximately 24V DC at the supply wire. Test for shorts to ground using the ohmmeter function—infinite resistance indicates proper insulation.

Step 3: Monitor Live Data with Diagnostic Software Connect Hitachi Dr.EX diagnostic software or equivalent tool to the machine's diagnostic port. Monitor real-time solenoid command values versus actual current draw. Compare commanded percentage (0-100%) against actual amperage feedback. Significant deviation indicates solenoid failure or ECM driver circuit malfunction.

Step 4: Harness Continuity and Routing Inspection Trace the wire harness from ECM (located behind the operator cab) to the pump solenoid. Pay special attention to the routing along the pump mounting bracket where harness chafing against metal edges is common in aged machines. Use a multimeter to verify continuity and check for intermittent opens by flexing the harness.

Step 5: Component Replacement and Validation If testing confirms solenoid failure, replace with genuine Hitachi pump control solenoid (Part #4286589 or equivalent). After installation, clear fault codes using diagnostic software and perform a pump calibration procedure per service manual specifications. Test under load to confirm code does not return.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific serial number and seek professional diagnostic assistance for complex electrical issues. Improper repairs can cause severe machine damage or safety hazards.