What is Hitachi ZX870LC-5A Fault Code 13311-4?

Fault Code 13311-4 on the Hitachi ZX870LC-5A indicates a hydraulic pump solenoid valve circuit malfunction, specifically detecting an abnormal current or short circuit condition in the main pump control system. This code is generated when the Electronic Control Module (ECM) detects irregular electrical signals from the proportional solenoid valve that regulates hydraulic pump displacement and system pressure.

This fault is critical for the ZX870LC-5A because the hydraulic pump solenoid directly controls the machine's work efficiency and power delivery. When this circuit malfunctions, the excavator cannot properly modulate hydraulic flow, leading to reduced performance, increased fuel consumption, and potential damage to the hydraulic main pump assembly. The ZX870LC-5A's advanced load-sensing system relies on precise solenoid control to match pump output with operator demand.

Common Symptoms

• Hydraulic power loss or noticeably reduced digging force and swing speed
• Erratic machine response to joystick inputs, with delayed or inconsistent movements
• Warning indicator illuminated on the instrument cluster, often accompanied by machine derate mode
• Increased engine RPM without corresponding increase in hydraulic performance
• Intermittent fault that may appear during cold starts or after extended operation under heavy loads

Potential Causes

The most common causes for Code 13311-4 on used ZX870LC-5A excavators include:

• Damaged wiring harness between the ECM and pump solenoid, particularly at known rub points near the main pump mounting area and along the engine firewall
• Failed proportional solenoid valve due to internal coil degradation or contamination from hydraulic fluid breakdown
• Corroded or loose electrical connectors at the pump solenoid terminals, especially on machines with high operating hours
• Shorted control circuit caused by chafed wiring insulation or moisture intrusion in the engine compartment
• ECM internal fault affecting the solenoid driver circuit (less common but possible on older units)
• Contaminated hydraulic oil causing solenoid spool sticking and abnormal current draw

How to Troubleshoot and Fix Code 13311-4

Step 1: Visual Inspection Begin by disconnecting the battery and inspecting the pump solenoid connector and wiring harness for obvious damage, corrosion, or oil contamination. On used excavators, check for harness wear at the pump mounting bracket and where cables pass through chassis grommets. Clean all connector pins with electrical contact cleaner.

Step 2: Electrical Testing Using a digital multimeter, measure solenoid coil resistance at the connector (disconnected from ECM). Typical resistance should be 3-8 ohms; consult your service manual for exact specifications. Check for short to ground by measuring resistance between each solenoid terminal and machine ground—it should read infinite (open circuit).

Step 3: Power Supply Verification Reconnect the harness and check for proper supply voltage (typically 12-24V depending on system) at the solenoid connector with ignition on. Measure voltage drop across the circuit during cranking to identify poor connections.

Step 4: Solenoid Function Test If electrical values are correct, remove the solenoid valve assembly and inspect for physical damage, contamination, or restricted movement. Replace hydraulic filter and fluid if contamination is evident, as this often damages solenoids in high-hour machines.

Step 5: ECM Diagnostics Use Hitachi diagnostic software (Dr.EX) to monitor real-time solenoid current draw and command signals. Compare actual versus commanded values to identify ECM driver circuit faults.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hitachi service manual for your specific machine serial number and consult qualified technicians for complex electrical or hydraulic repairs. Improper diagnosis can lead to costly component damage.