What is Hyundai HX220 NL EPFC Fault Code 1117 (627-3)?

Fault Code 1117 (627-3) indicates a Fuel Injector #3 Circuit Malfunction or abnormal current detection in the third cylinder's fuel injection system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects that the electrical signal to the fuel injector solenoid on cylinder #3 is outside the manufacturer's specified parameters—either an open circuit, short circuit, or incorrect resistance value.

This code is critical for the Hyundai HX220 NL EPFC because improper fuel delivery to cylinder #3 directly impacts combustion efficiency, leading to reduced power output, increased fuel consumption, and potential damage to the common rail fuel system. The ECM monitors injector current in real-time, and any deviation triggers this fault to prevent engine damage.

Common Symptoms

• Engine power derate or noticeable loss of hydraulic performance during digging operations
• Rough idle or misfiring, particularly noticeable when the machine is under load
• Check Engine Light (CEL) illuminated on the instrument cluster with potential audible warning alarm
• Increased black or white smoke from the exhaust during operation
• Fuel consumption increase without corresponding workload changes

Potential Causes

The most common causes for Code 1117 on used HX220 excavators include:

• Faulty fuel injector solenoid on cylinder #3 due to coil winding failure or internal short circuit
• Damaged wiring harness between the ECM and injector #3—common wear points include routing near the valve cover where vibration causes insulation breakdown
• Corroded or loose electrical connectors at the injector plug, especially on machines with high hours in wet or dusty environments
• ECM internal driver circuit failure for the #3 injector channel (less common but possible on high-hour machines)
• Incorrect injector resistance due to contaminated fuel causing internal injector damage
• Chafed wires at harness support brackets near the fuel rail assembly

How to Troubleshoot and Fix Code 1117 (627-3)

Step 1: Visual Inspection Begin by inspecting the wiring harness and connector at fuel injector #3. Look for obvious damage, corrosion on pins, oil contamination in the connector boot, or wire chafing near mounting brackets. On used excavators, check for previous repair attempts like electrical tape or wire splices that may have degraded.

Step 2: Resistance Testing Disconnect the injector connector and use a digital multimeter to measure resistance across the injector solenoid terminals. Hyundai injectors typically spec between 0.3-0.7 ohms (consult service manual for exact specs). Compare cylinder #3 readings with other injectors—significant deviation indicates injector replacement is needed.

Step 3: Wiring Continuity Check With the injector disconnected, check continuity from the ECM connector to the injector harness plug. Also test for shorts to ground or shorts to power on both injector wires. Pay special attention to harness routing near the engine block where heat and vibration cause insulation failure.

Step 4: ECM Signal Testing Using Hyundai diagnostic software (Hi-SOS or compatible scan tool), perform an injector actuation test while monitoring current draw. The ECM should pulse the injector with specific amperage—abnormal current patterns indicate ECM driver failure.

Step 5: Component Replacement If testing confirms injector failure, replace the fuel injector assembly with OEM or quality aftermarket parts. Always replace the copper sealing washer and O-rings. If wiring is damaged, repair using OEM-spec wire and heat-shrink connectors—never use crimp connectors in high-vibration environments.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Hyundai service manual for your specific machine serial number. If unfamiliar with high-pressure fuel systems or electrical diagnostics, consult a certified heavy equipment technician to avoid injury or further damage.