What is Hyundai HX220 NL EPFC Fault Code 4517 (237-13)?

Fault Code 4517 (237-13) indicates an Auxiliary Hydraulic Solenoid Valve Circuit Malfunction in the Hyundai HX220 NL EPFC excavator. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal electrical signal—either an open circuit, short circuit, or out-of-range voltage—in the auxiliary hydraulic solenoid valve control circuit.

This code specifically affects the proportional control system that regulates auxiliary hydraulic functions such as breakers, grapples, or shears. The HX220's EPFC (Electronic Proportional Flow Control) system relies on precise voltage signals between 0.5-4.5V to modulate hydraulic flow. When circuit integrity is compromised, the ECM cannot properly command the solenoid valve, resulting in loss of auxiliary function control and potential system shutdown to prevent hydraulic damage.

Common Symptoms

• Auxiliary hydraulic attachment becomes completely unresponsive or operates erratically with inconsistent flow rates
• Diagnostic warning light illuminates on the instrument cluster with fault code display
• Hydraulic system derate mode activates, limiting main boom and arm functions to protect the system
• Intermittent operation where the attachment works briefly then stops, especially when machine vibrates or moves
• Error message on monitor screen specifically referencing auxiliary circuit or solenoid valve failure

Potential Causes

The most common technical failures triggering Code 4517 in used HX220 excavators include:

• Damaged wiring harness at the boom base pivot point where cables flex repeatedly, causing conductor breakage or insulation wear
• Corroded connector pins at the solenoid valve plug (C237) due to water ingress from worn cab floor seals
• Failed proportional solenoid valve coil with internal winding breakdown (resistance should measure 8-12 ohms)
• Chafed wires rubbing against the hydraulic tank mounting bracket—a known wear point on HX220 models
• ECM internal driver circuit failure affecting only the auxiliary output channel (less common but possible in high-hour machines)
• Voltage supply issues from corroded ground connections at G104 grounding point near the battery box

How to Troubleshoot and Fix Code 4517 (237-13)

Step 1: Visual Harness Inspection Thoroughly inspect the auxiliary solenoid valve wiring harness from the cab floor connector through the boom base. Look specifically for abraded insulation, exposed copper, or oil-soaked wires near hydraulic lines. Check connector C237 for bent pins, corrosion (green deposits), or moisture inside the boot.

Step 2: Electrical Testing with Multimeter Disconnect the solenoid valve connector. Measure coil resistance across the solenoid terminals—specification is 8-12 ohms at 20°C. Then check for voltage supply: key on, engine off should show 12V at the harness side connector. Finally, test for short to ground by measuring resistance between each wire and chassis ground (should read >10k ohms).

Step 3: Signal Verification and Repair Using Hyundai Hi-MATE diagnostic software or compatible scan tool, perform an active test commanding the solenoid valve while monitoring voltage output. Proper operation shows 0.5-4.5V modulation. For used excavators, pay special attention to harness flex points—replace entire harness sections rather than splicing if wire strands are broken. Clean all ground connections at G104 with wire brush and apply dielectric grease.

Step 4: Component Replacement Protocol If diagnostics confirm solenoid failure, replace with genuine Hyundai part number or OEM-equivalent valve. Before installation on used machines, verify hydraulic oil cleanliness (contamination can damage new solenoids). After replacement, clear codes, perform relearn procedure via diagnostic software, and cycle attachment through full operation range.

---

Disclaimer: This guide provides general diagnostic information. Complex electrical issues or ECM programming should be performed by certified Hyundai heavy equipment technicians with proper diagnostic tools and safety equipment. Always consult the official service manual for your specific machine serial number.