What is XCMG General Fault Code E1144?

Fault Code E1144 indicates a communication error or signal fault in the hydraulic system control module, specifically related to the main pump pressure sensor circuit or proportional valve feedback signal. This diagnostic trouble code (DTC) is triggered when the Electronic Control Unit (ECU) detects an abnormal voltage reading, open circuit, or data transmission failure between the hydraulic control system and the machine's central monitoring system.

In XCMG excavators, this code directly affects the machine's ability to regulate hydraulic pump output and maintain optimal flow rates to the boom, arm, and bucket circuits. When E1144 activates, the ECU may enter a protective derate mode to prevent hydraulic system damage, significantly reducing operational efficiency and potentially causing erratic hydraulic response during critical lifting or digging operations.

Common Symptoms

• Hydraulic system derate with noticeably reduced boom or arm speed, even at full throttle
• Warning indicator illuminated on the instrument cluster, often accompanied by an audible alarm
• Erratic or sluggish hydraulic response, particularly during combined multi-function operations
• Intermittent loss of hydraulic power that may reset after machine restart, indicating loose connections
• Engine may continue running normally, but hydraulic functions operate at reduced capacity or fail to respond

Potential Causes

The most common technical causes for E1144 on used XCMG excavators include:

• Faulty main pump pressure sensor due to internal diaphragm failure or contamination from hydraulic fluid debris
• Damaged wiring harness between the pressure sensor and ECU, especially at flex points near the pump mounting area where vibration causes conductor breakage
• Corroded or loose electrical connectors at the sensor plug or ECU interface, common in machines with high hour counts or exposure to moisture
• Proportional solenoid valve malfunction causing feedback signal discrepancies
• ECU software glitches or corrupted calibration files, particularly in older firmware versions
• Hydraulic contamination affecting sensor accuracy or causing internal valve sticking

How to Troubleshoot and Fix Code E1144

Step 1: Initial Diagnostic Scan Connect XCMG-compatible diagnostic software (such as XCMG Service Tool or equivalent OBD interface) to retrieve freeze frame data. Record the exact operating conditions when E1144 was logged, including engine RPM, hydraulic temperature, and active functions.

Step 2: Visual and Physical Inspection Inspect the main pump pressure sensor (typically located on the main hydraulic pump body) for physical damage, oil leaks, or loose mounting. Check the entire wiring harness from sensor to ECU for abrasion, especially where it passes near moving components or sharp edges. On used excavators, pay special attention to connector corrosion—disconnect plugs and inspect pins for green oxidation or bent terminals.

Step 3: Electrical Testing Using a digital multimeter, perform voltage and resistance checks:

• Measure sensor supply voltage (should be 5V ±0.25V with key on, engine off)
• Check signal wire continuity between sensor and ECU (should read <5 ohms)
• Test sensor output voltage at idle and under load (typical range 0.5V-4.5V depending on pressure)

Step 4: Component Testing and Replacement If electrical values are abnormal, replace the pressure sensor with OEM or quality equivalent parts. For intermittent codes on high-hour machines, consider replacing the entire sensor-to-ECU harness section to eliminate age-related conductor fatigue. Clear codes and perform a hydraulic system function test under load.

Step 5: Verify Hydraulic System Integrity Check hydraulic oil quality and filter condition—contaminated fluid can damage sensors. Verify proportional valve operation using diagnostic software to command valve positions and observe feedback signals.

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Disclaimer: This guide provides general troubleshooting information for XCMG fault code E1144. Hydraulic and electrical system diagnostics require proper training and tools. Always consult the official XCMG service manual for your specific model and consider professional assistance for complex repairs, especially on used equipment where multiple underlying issues may exist.