What is XCMG XE750D Fault Code 2344 SPN2955 FMI6?

Fault Code 2344 (SPN 2955 FMI 6) indicates a calibration or data issue with the Aftertreatment Diesel Particulate Filter (DPF) Differential Pressure Sensor on the XCMG XE750D excavator. SPN 2955 specifically refers to the Aftertreatment 1 Diesel Particulate Filter Differential Pressure, while FMI 6 denotes a calibration fault or data error within the sensor's signal range.

This fault code is critical for the XE750D's emission control system, as the DPF differential pressure sensor monitors the pressure difference across the diesel particulate filter to determine soot accumulation levels. When the Engine Control Module (ECM) detects incorrect calibration data or out-of-range signals from this sensor, it triggers this code. For a machine of this size operating in demanding construction environments, maintaining proper DPF regeneration cycles is essential for preventing costly engine derates and ensuring compliance with emission standards.

Common Symptoms

• Check Engine Light (CEL) or DPF warning lamp illuminated on the instrument cluster
• Engine derate mode activated, resulting in reduced power output (typically 25-40% power loss)
• Frequent or failed DPF regeneration attempts, causing operational interruptions
• Excessive black smoke from the exhaust during acceleration or load conditions
• Error messages on the display indicating aftertreatment system malfunction

Potential Causes

The most common technical causes for this fault code on used XCMG XE750D excavators include:

• Faulty DPF differential pressure sensor due to carbon buildup, heat damage, or internal component failure
• Damaged or corroded wiring harness at connector points, especially near the DPF housing where high temperatures and vibration cause wear
• ECM calibration errors following software updates or battery disconnection events
• Blocked or kinked pressure sensor hoses connecting the sensor to the DPF inlet and outlet ports
• Contaminated sensor ports from oil residue, coolant leaks, or debris intrusion in older machines
• Faulty ECM with corrupted calibration data (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code 2344 SPN2955 FMI6

Step 1: Visual Inspection Begin by inspecting the DPF differential pressure sensor located on or near the DPF canister. Check all wiring harnesses and connectors for damage, corrosion, or oil contamination. On used excavators, pay special attention to harness routing where cables may rub against the frame or exhaust components. Inspect the pressure sensing hoses for cracks, kinks, or blockages.

Step 2: Sensor and Circuit Testing Using a digital multimeter, check the sensor's supply voltage (typically 5V) and ground circuit at the sensor connector with the ignition on. Verify the signal wire shows a voltage reading between 0.5V and 4.5V. Compare resistance values against XCMG specifications (typically 1000-3000 ohms depending on temperature). Check for short circuits or open circuits in the wiring back to the ECM.

Step 3: Clear Code and Monitor Connect XCMG-approved diagnostic software (or compatible heavy equipment scan tool) to the machine's diagnostic port. Clear the fault code and perform a DPF system calibration or sensor relearn procedure as specified in the service manual. Monitor live data to ensure the sensor reads correctly during idle and under load.

Step 4: Component Replacement If the sensor tests reveal faulty readings or calibration cannot be completed, replace the DPF differential pressure sensor with a genuine XCMG or OEM-equivalent part. For used machines with high hours, also replace the pressure sensing hoses and clean the DPF ports. After installation, perform an ECM reset and forced DPF regeneration to verify proper system operation.

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Disclaimer: This guide provides general diagnostic information for reference purposes. Always consult the official XCMG XE750D service manual and consider professional diagnosis by a certified heavy equipment technician, especially for complex emission system repairs involving ECM programming or DPF replacement.