What is XCMG XE750D Fault Code E1379(1) SPN168 FMI17?

Fault Code E1379(1) with SPN168 FMI17 indicates a data validity issue with the battery voltage signal being transmitted on the CAN network. Specifically, SPN 168 refers to the electrical system's battery voltage parameter, while FMI 17 denotes "Data Valid But Above Normal Operating Range - Moderately Severe Level."

This fault code signals that the Engine Control Module (ECM) is receiving battery voltage readings that exceed acceptable operational thresholds on the XCMG XE750D excavator. The electrical system is the lifeblood of modern excavators, powering critical components including the ECM, hydraulic solenoids, and sensor networks. When voltage readings become erratic or excessively high, it can trigger protective protocols that limit machine performance or cause unexpected shutdowns. This is particularly critical on the XE750D's 24-volt electrical architecture, where voltage regulation directly impacts the longevity of expensive electronic control modules.

Common Symptoms

• Warning lamp illumination on the instrument cluster, often accompanied by a check engine light or electrical system alert
• Intermittent loss of communication between the ECM and other control modules, causing erratic hydraulic responses
• Engine derating or reduced power output as the ECM enters protective mode to prevent electrical component damage
• Difficulty starting or unusual cranking behavior, especially after the machine has been sitting overnight
• Flickering displays or unstable gauge readings on the operator monitor during operation

Potential Causes

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

• Failing alternator or voltage regulator producing inconsistent charging voltage above 28.5-29 volts
• Damaged wiring harness near the battery box or alternator mounting points where cable insulation deteriorates from vibration and heat exposure
• Corroded battery terminals or ground connections creating voltage spikes during electrical load changes
• Faulty battery disconnect relay causing voltage fluctuations when switching between power sources
• Aging batteries with internal short circuits that cannot maintain stable voltage under load
• ECM power supply circuit issues, including damaged connectors at the control module itself
• Aftermarket electrical accessories improperly wired into the main power distribution system

How to Troubleshoot and Fix Code E1379(1) SPN168 FMI17

Step 1: Measure Actual Battery Voltage

Using a digital multimeter (DMM), check battery voltage with the engine off (should read 24-26V) and during operation (should read 27-28.5V maximum). If readings exceed 29 volts during operation, the alternator voltage regulator is likely faulty. On used excavators, also inspect the battery cables for green corrosion at crimp points—a common failure point after 5,000+ operating hours.

Step 2: Inspect the Charging System Components

Test the alternator output directly at the alternator terminals while the engine runs at high idle. Compare readings to XCMG specifications (typically 27.5-28V). Check the voltage regulator connector for moisture intrusion or pin corrosion. On the XE750D, this connector is located near the alternator housing and frequently suffers from seal deterioration in dusty environments.

Step 3: Examine Wiring Harness and Ground Connections

Physically trace the main power harness from the batteries to the ECM, looking for chafing points against the frame rails or hydraulic lines. Pay special attention to the ground strap connections at the engine block and chassis—loose or corroded grounds create voltage reference errors. Remove, clean with electrical contact cleaner, and re-torque all battery terminal connections and ground points to manufacturer specifications.

Step 4: Check for Parasitic Electrical Loads

Disconnect aftermarket accessories and test if the fault clears. Improperly installed work lights, radios, or tracking devices can create voltage irregularities. Use an ammeter to check for excessive current draw with the key off (should be less than 50mA).

Step 5: Verify ECM Power Supply Circuit

Inspect the ECM power connector (typically a multi-pin Deutsch connector) for bent pins, corrosion, or heat damage. Check voltage stability at the ECM power pins during cranking—voltage should not drop below 22V. Replace connector seals if moisture is present.

Step 6: Battery and Relay Testing

Perform a load test on both batteries using a carbon pile tester. Batteries should maintain at least 9.6V per 12V battery under 50% load for 15 seconds. Test the battery disconnect relay operation with a multimeter—contacts should show less than 0.5 ohms resistance when energized.

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Disclaimer: This guide provides general diagnostic information for XCMG XE750D fault code E1379(1) SPN168 FMI17. Electrical system diagnosis can be complex, and improper repairs may cause additional damage. Always consult the official XCMG service manual and consider professional diagnostic assistance, especially when dealing with high-voltage systems on used equipment where previous repairs may affect current troubleshooting procedures.