What is XCMG XE750D Fault Code 3105-4 SPN4360 FMI4?

Fault Code 3105-4 (SPN 4360 FMI 4) indicates a voltage problem below normal range or shorted to ground in the Exhaust Gas Recirculation (EGR) valve actuator circuit. This code is part of the J1939 diagnostic standard used in modern diesel engines and specifically relates to the EGR system's electrical control circuit on the XCMG XE750D excavator.

SPN 4360 refers to the EGR Valve Actuator Position, while FMI 4 specifies that the Engine Control Module (ECM) has detected voltage levels below the expected threshold or a short circuit to ground. The EGR system is critical for emissions control and engine efficiency, recirculating exhaust gases to reduce combustion temperatures and NOx emissions. When this circuit malfunctions, the ECM cannot properly control exhaust gas flow, potentially affecting engine performance, fuel efficiency, and emissions compliance on this 75-ton class excavator.

Common Symptoms

• Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL) illuminated on the dashboard
• Engine derate mode engaged, limiting power output to 75% or lower to protect the engine
• Rough idle or irregular engine running, particularly noticeable during warm-up
• Increased black or gray exhaust smoke due to improper combustion temperatures
• Poor throttle response or hesitation during acceleration under load

Potential Causes

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

• Damaged or corroded wiring harness at the EGR valve connector, especially where the harness routes near the engine block or exhaust manifold (known rub point)
• Failed EGR valve actuator motor due to carbon buildup or internal electrical failure
• Shorted or grounded wiring in the actuator circuit between the ECM and EGR valve
• Corroded or loose electrical connectors at the EGR valve or ECM terminals (common in machines with high hours)
• Faulty ECM pins or internal ECM damage (less common but possible in older units)
• Water intrusion into the connector housing from damaged seals or improper cleaning

How to Troubleshoot and Fix Code 3105-4 SPN4360 FMI4

Step 1: Visual Inspection Begin by locating the EGR valve on the engine (typically mounted on the intake manifold). Inspect the wiring harness from the valve back to the ECM for visible damage, abrasion, pinching, or corrosion. On used excavators, pay special attention to areas where the harness contacts metal surfaces or heat sources. Check the connector pins for bent terminals, corrosion (green/white buildup), or moisture inside the connector boots.

Step 2: Electrical Testing Disconnect the EGR valve actuator connector. Using a digital multimeter (DMM), measure resistance across the actuator terminals. Typical resistance should be between 10-30 ohms (consult XCMG service manual for exact specifications). Infinite resistance indicates an open circuit inside the actuator. Next, check for shorts to ground by measuring resistance between each actuator terminal and engine ground—readings should be greater than 10,000 ohms. Any lower reading confirms a ground short in the wiring or actuator.

Step 3: Voltage Supply Check Reconnect the harness and backprobe the connector with the ignition on (engine off). Verify the ECM is supplying proper voltage (typically 12V reference) to the actuator. If voltage is absent or below 10V, trace the circuit back toward the ECM checking for damaged wires or poor connections. For used machines, remove and clean all connectors with electrical contact cleaner and apply dielectric grease to prevent future corrosion.

Step 4: Component Replacement If the actuator tests faulty, replace the EGR valve assembly with a genuine XCMG or quality aftermarket part. If wiring is damaged, repair using OEM-spec wire and heat-shrink connectors—avoid simple electrical tape on diesel equipment. After repairs, clear the fault code using XCMG diagnostic software or a compatible J1939 scan tool and perform a stationary regeneration if available to verify proper EGR operation.

Disclaimer: This guide provides general diagnostic procedures. Always consult the official XCMG service manual for your specific machine serial number and consider professional diagnosis if you lack proper diagnostic tools or experience with high-voltage diesel systems.