What is Hyundai HX220 NL EPFC Fault Code 1695 (3513-3)?

Fault Code 1695 (3513-3) indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically related to abnormal voltage or data transmission errors within the machine's CAN (Controller Area Network) bus system. This code is part of Hyundai's electronic diagnostic system and signals that the ECM is either not receiving proper signals from connected sensors and modules, or there's a voltage irregularity affecting the communication network.

This fault is critical for the HX220 NL EPFC because the CAN bus serves as the central nervous system for all electronic components—from engine sensors to hydraulic controllers. When communication breaks down, the machine's Electronic Power Flow Control (EPFC) system cannot properly coordinate engine performance with hydraulic demand, leading to reduced efficiency and potential safety issues. In used excavators, this code often emerges due to age-related wiring degradation or connector corrosion.

Common Symptoms

• Dashboard warning lights: The check engine light or ECM malfunction indicator illuminates continuously
• Erratic engine behavior: Unexpected RPM fluctuations, rough idling, or engine derating (power reduction mode)
• Hydraulic response issues: Sluggish or inconsistent hydraulic movements despite proper operator input
• Intermittent gauge failures: Fuel level, temperature, or pressure gauges displaying incorrect readings or going blank
• Communication errors on diagnostic displays: Multiple unrelated fault codes appearing simultaneously

Potential Causes

The most common technical reasons for Code 1695 (3513-3) on used HX220 excavators include:

• Corroded or damaged CAN bus wiring harness, particularly at flex points near the engine bay or boom pivot areas where cables experience repeated bending
• Failed or failing ECM power supply circuit, often caused by voltage spikes from aging alternators or poor grounding connections
• Defective CAN bus termination resistors within the network, causing signal reflection and data corruption
• Water intrusion into main harness connectors, common on machines operated in wet conditions without proper maintenance
• Worn ECM internal circuits or capacitor degradation in high-hour machines (typically above 8,000 hours)

How to Troubleshoot and Fix Code 1695 (3513-3)

Step 1: Visual Inspection and Connector Check Begin by thoroughly inspecting all wiring harnesses connected to the ECM and major control modules. On used excavators, focus on known wear points: cables routing along the right-side frame rail and connections behind the operator cab. Look for chafed insulation, green corrosion on pins, or loose connector locks. Clean all CAN bus connectors with electrical contact cleaner and apply dielectric grease.

Step 2: Voltage and Resistance Testing Using a digital multimeter, check the ECM power supply. With the key on/engine off, verify battery voltage (12-14V) at the ECM main connector. Test CAN High and CAN Low lines—they should show approximately 2.5V at rest with equal resistance (around 60 ohms) between them when the system is powered down. Significant deviation indicates a short circuit or open circuit condition.

Step 3: CAN Bus Continuity and Termination Check Disconnect the battery and measure resistance across the CAN High and CAN Low wires at the ECM connector. You should read approximately 120 ohms if termination resistors are intact. If readings are infinite or near-zero, locate and replace faulty termination resistors typically found at network endpoints (ECM and display panel).

Step 4: Advanced Diagnostics with Manufacturer Software Connect Hyundai Hi-MATE or equivalent diagnostic software to monitor live CAN bus traffic. Look for communication dropouts, error frames, or modules failing to respond. If intermittent faults appear, perform a "wiggle test" on harnesses while monitoring—this often reveals fractured wires inside intact insulation, a common issue in used machines.

Step 5: ECM Replacement Consideration If all wiring, grounds, and termination resistors test correctly, the ECM itself may have internal failures. Before replacement, verify the ECM part number matches your specific HX220 NL EPFC variant, as software versions are model-specific. Consider sourcing a tested used ECM or professional ECM repair services, as new units can exceed $2,000.

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Disclaimer: This guide provides general troubleshooting procedures for informational purposes. Always consult the official Hyundai service manual for your specific machine serial number and consider professional diagnostic services for complex electrical issues, especially when dealing with critical engine control systems.