What is Hyundai HX220 NL EPFC Fault Code 4713 (5357-31)?

Fault Code 4713 (5357-31) on the Hyundai HX220 NL EPFC indicates a malfunction in the Engine Controller (ECM) communication circuit, specifically related to CAN (Controller Area Network) bus communication failure or irregular signal transmission between the engine control module and other critical machine systems.

This code is part of Hyundai's electronic fuel injection and power control system (EPFC), which manages engine performance, emissions, and hydraulic coordination. The 5357-31 designation typically refers to CAN communication line voltage irregularities or complete signal loss between the ECM and the machine's main controller. For the HX220 NL model, this is critical because the excavator relies on seamless data exchange between controllers to maintain proper engine load management, fuel delivery timing, and hydraulic response. When this communication breaks down, the machine cannot optimize performance or protect itself from operating outside safe parameters.

Common Symptoms

When Code 4713 (5357-31) is active, operators typically experience:

• Check Engine Light or Master Warning Light illuminated on the instrument cluster
• Sudden engine derate or power reduction mode, limiting RPM to protect the engine
• Erratic hydraulic response or sluggish boom/arm movements due to ECM-hydraulic controller miscommunication
• Intermittent engine stalling or failure to start, especially after the machine has warmed up
• Display screen errors showing "Communication Error" or blank gauge readings for engine parameters

Potential Causes

The most common technical causes for this fault code on used Hyundai HX220 excavators include:

• CAN bus wiring harness damage at known rub points near the engine firewall or along the right-side chassis rail where harnesses contact frame edges
• Corroded or loose connector pins at the ECM main harness plug (C101 connector), particularly in machines exposed to moisture or salt environments
• Faulty ECM ground connections (G201 ground point) causing voltage reference issues
• Failed termination resistor in the CAN network (120-ohm resistor failure)
• ECM internal failure due to voltage spikes or age-related component degradation in older units
• Aftermarket accessory interference if non-OEM electronics were spliced into the CAN network

How to Troubleshoot and Fix Code 4713 (5357-31)

Step 1: Visual Harness Inspection
Begin by thoroughly inspecting the main engine harness from the ECM (located behind the right-side access panel) to the machine controller under the cab. Look for abraded insulation, particularly where the harness passes through the engine bay firewall grommet. On used HX220s, check for oil contamination on connectors, which degrades seals and causes corrosion.

Step 2: Connector and Ground Testing
Disconnect the ECM connector C101 and inspect all pins for corrosion, bent contacts, or moisture intrusion. Using a digital multimeter, verify the ECM ground circuit (G201) has less than 0.5 ohms resistance to chassis ground. Check CAN-High and CAN-Low wire continuity (typically pins 23 and 24 on the ECM connector) for opens or shorts to ground.

Step 3: CAN Bus Voltage and Resistance Check
With the ignition key ON (engine off), measure CAN-High voltage (should read approximately 2.5-3.5V) and CAN-Low voltage (approximately 1.5-2.5V) at the ECM connector. Measure resistance between CAN-High and CAN-Low with all controllers disconnected—you should read approximately 60 ohms (two 120-ohm termination resistors in parallel). Readings outside this range indicate termination resistor failure or harness shorts.

Step 4: Diagnostic Software Scan
Connect Hyundai Hi-MATE or compatible diagnostic software to verify real-time CAN communication status. Monitor for intermittent dropouts while wiggling harnesses—this reveals vibration-induced connection failures common in used machines.

Step 5: Component Replacement
If diagnostics confirm harness integrity but communication fails, the ECM itself may require replacement. For used excavators, always verify the replacement ECM part number and software version matches your machine's specification, as incorrect ECM programming will trigger additional fault codes.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Hyundai service manual for your specific machine serial number and consider engaging a certified Hyundai technician for complex electrical diagnostics. Improper repairs to CAN bus systems can cause cascading electronic failures.