XCMG Excavator Fault Code 325-4: Complete Diagnostic Guide

What is XCMG Fault Code 325-4?

Fault Code 325-4 indicates a hydraulic pump pressure sensor circuit malfunction or abnormal pressure reading in the main hydraulic system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects voltage signals outside the expected range from the main pump pressure sensor, typically between 0.5-4.5 volts during normal operation.

This code is critical for XCMG excavators because the hydraulic pump pressure sensor directly controls load-sensing functions, affecting everything from swing speed to bucket breakout force. When this sensor fails, the ECM cannot properly regulate hydraulic flow, leading to performance degradation and potential component damage.

Common Symptoms

When Code 325-4 is active, operators typically experience:

• Erratic hydraulic performance with inconsistent boom, arm, or bucket speeds
• Warning light illumination on the instrument cluster (typically orange/amber hydraulic icon)
• Reduced engine power or automatic derate mode to protect the hydraulic system
• Sluggish or jerky movements during multi-function operations
• Fault code display on the monitor screen with possible audible alarm

Potential Causes

The most common technical reasons for Code 325-4 in used XCMG excavators include:

• Pressure sensor internal failure due to vibration fatigue or seal deterioration (common after 5,000+ hours)
• Damaged wiring harness near the hydraulic pump area where cables rub against mounting brackets
• Corroded connector pins at the sensor plug, especially on machines exposed to wet environments
• Voltage supply issues from the ECM 5-volt reference circuit
• Contaminated hydraulic oil causing sensor diaphragm damage
• ECM software calibration errors or stored corrupted data

How to Troubleshoot and Fix Code 325-4

Step 1: Visual Inspection
Locate the main pump pressure sensor (typically mounted on the main control valve or pump housing). Inspect the wiring harness for abrasion, cuts, or heat damage. On used excavators, check where harnesses pass over sharp edges—this is a common failure point. Examine the connector for oil contamination, bent pins, or green corrosion.

Step 2: Electrical Testing
Using a multimeter, backprobe the sensor connector with the key on, engine off. Verify 5-volt reference supply from the ECM (Pin 1) and good ground continuity (Pin 2, should read <0.5 ohms to chassis). Check signal wire voltage (Pin 3)—it should read approximately 0.8-1.2 volts at rest.

Step 3: Live Data Analysis
Connect XCMG diagnostic software (or compatible scan tool) and monitor live pressure sensor values. Start the engine and compare readings against actual hydraulic pressure using a mechanical pressure gauge installed at the test port. Deviation greater than 10% indicates sensor failure.

Step 4: Component Replacement
If the sensor is faulty, replace with OEM or equivalent pressure transducer (typically 0-350 bar range for XCMG). Before installation, clean the mounting port and apply anti-seize compound to threads. Clear codes and perform a calibration routine through the diagnostic software.

For used excavators: Always inspect O-rings and sealing surfaces for wear before reinstalling components, as minor leaks can cause recurring codes.

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Disclaimer: This guide provides general diagnostic information. Always consult the official XCMG service manual for your specific model and serial number. If unfamiliar with high-pressure hydraulic systems or electrical diagnostics, seek assistance from a certified heavy equipment technician.