What is Hitachi ZX470LCH-5G Fault Code 13304-2?

Fault Code 13304-2 indicates a hydraulic pump solenoid valve circuit malfunction in the Hitachi ZX470LCH-5G excavator, specifically related to abnormal voltage or current flow in the pump control system. This diagnostic trouble code (DTC) is triggered when the machine's Electronic Control Module (ECM) detects irregular electrical signals from the hydraulic pump's proportional solenoid valve circuit, which directly controls hydraulic flow and pressure distribution.

This code is critical for the ZX470LCH-5G because this model uses an advanced closed-center load-sensing hydraulic system that relies on precise electronic control of pump displacement. When code 13304-2 appears, the excavator's performance suffers significantly as the ECM may limit hydraulic output to prevent system damage, resulting in reduced operational capability and potential job site delays.

Common Symptoms

When fault code 13304-2 is active on your Hitachi ZX470LCH-5G, operators typically experience:

• Reduced hydraulic power across all functions (boom, arm, bucket, and swing operations feel sluggish)
• Hydraulic warning light illuminated on the instrument cluster with possible audible alarm
• Engine derate mode activation, limiting RPM to protect the hydraulic system
• Erratic hydraulic response where functions may work intermittently or with inconsistent speed
• Increased fuel consumption due to inefficient pump operation and compensatory throttle inputs

Potential Causes

The most common technical reasons for code 13304-2 on used ZX470LCH-5G excavators include:

• Solenoid valve coil failure due to thermal stress or internal short circuit (resistance typically measures outside 3-7 ohms specification)
• Damaged wiring harness near the main pump area where vibration causes conductor breakage or insulation wear
• Corroded electrical connectors at the pump solenoid, especially on machines operated in coastal or high-humidity environments
• ECM internal relay failure affecting the solenoid driver circuit
• Voltage supply issues from the main power harness (should maintain 24V DC ±2V)
• Hydraulic contamination causing mechanical binding of the solenoid spool, increasing electrical load

How to Troubleshoot and Fix Code 13304-2

Step 1: Initial Inspection and Code Verification Connect Hitachi Dr.EX diagnostic software to the machine's diagnostic port and verify code 13304-2 is current (not historical). Record freeze frame data showing operating conditions when the fault occurred. Visually inspect the hydraulic pump solenoid connector for obvious corrosion, bent pins, or oil contamination—common on used excavators with 5,000+ hours.

Step 2: Electrical Testing of Solenoid Circuit Disconnect the solenoid valve connector and measure coil resistance using a digital multimeter—specification should be 3-7 ohms at room temperature. Next, check for voltage supply at the harness side connector with ignition on; you should see approximately 24V DC. Inspect the ground circuit for continuity to chassis ground (should read less than 1 ohm resistance).

Step 3: Harness and Connector Inspection On used ZX470LCH-5G machines, carefully inspect the wiring harness routing from the ECM to the pump solenoid. Pay special attention to areas where the harness passes near the engine mount or hydraulic tank—these are known rub points. Look for chafed insulation, broken wire strands, or evidence of previous repairs with electrical tape.

Step 4: Component Replacement and System Reset If electrical tests reveal out-of-specification readings, replace the faulty component (solenoid valve, harness section, or repair connector). For used equipment, always apply dielectric grease to connectors during reassembly to prevent future corrosion. Clear fault codes using diagnostic software and perform a function test under load to verify repair.

Disclaimer: This guide provides general troubleshooting information. Always consult the Hitachi ZX470LCH-5G service manual for exact specifications and safety procedures. Complex hydraulic and electrical diagnostics should be performed by certified technicians with proper training and equipment.