What is Komatsu PC220-7 Fault Code E-17?

Fault Code E-17 on the Komatsu PC220-7 indicates a malfunction in the engine controller (ECM) communication circuit, specifically a communication error between the engine ECM and the machine controller (MCU). This code is triggered when the Controllers Area Network (CAN) bus experiences data transmission failures or signal interruptions between these critical control modules.

The PC220-7 relies on seamless communication between the engine ECM and machine controller to coordinate hydraulic functions, engine performance, and safety systems. When this communication link fails, the excavator cannot properly regulate engine output relative to hydraulic demand, potentially causing reduced efficiency, operational limitations, and diagnostic difficulties. This fault is particularly critical because it affects the machine's integrated control system, which optimizes fuel consumption and prevents component damage through coordinated system management.

Common Symptoms

• Monitor panel displays E-17 error code with simultaneous illumination of the warning lamp
• Reduced engine power or automatic derating to protect systems during communication failures
• Erratic hydraulic performance, including inconsistent swing speed or boom/arm response
• Intermittent gauge failures on the monitor display (fuel level, temperature, or hour meter malfunctions)
• Engine may start normally but enter limp mode under load conditions

Potential Causes

The most common causes of E-17 on used PC220-7 excavators include:

• Damaged or corroded CAN bus wiring harness, particularly at routing points near the battery box or cab floor where harnesses experience vibration and moisture exposure
• Loose or oxidized connector terminals at the ECM (located right side of engine) or MCU (behind monitor panel)
• Failed termination resistor in the CAN network causing signal reflection and data corruption
• ECM or MCU controller failure, though less common than wiring issues in used machines
• Voltage irregularities from weak batteries or failing alternators affecting controller communication stability
• Previous repair modifications where non-OEM harnesses were spliced incorrectly

How to Troubleshoot and Fix Code E-17

Step 1: Visual Inspection Begin by inspecting the main wiring harness routing between the engine bay and operator cab. Check for obvious damage, abrasion points where harnesses contact frame members, or evidence of rodent damage. On used excavators, pay special attention to harness routing near the dozer cylinder and areas with cable ties that may have deteriorated, allowing wire movement and chafing.

Step 2: Connector Examination Disconnect and inspect the 20-pin ECM connector and MCU connectors behind the monitor. Look for pin corrosion, pushed-back pins, or moisture intrusion. Clean connectors with electrical contact cleaner and apply dielectric grease. This simple step resolves approximately 40% of E-17 codes on older machines.

Step 3: CAN Bus Testing Using a digital multimeter, measure CAN High and CAN Low circuit resistance. With ignition off and connectors disconnected, you should read approximately 60 ohms between CAN-H and CAN-L, indicating proper termination resistors. Resistance significantly higher suggests open circuit or failed terminator; lower readings indicate a short circuit.

Step 4: Voltage Verification With ignition on, check for proper supply voltage (12V) and ground continuity at both ECM and MCU. Voltage drops exceeding 0.5V indicate poor ground connections—common in used machines due to corrosion at frame ground points.

Step 5: Advanced Diagnostics Connect Komatsu KOMTRAX diagnostic software or compatible scan tool to monitor real-time CAN bus traffic. Intermittent communication dropouts visible in data streams indicate harness issues rather than controller failures. Check for fault code history to determine if the error is constant or intermittent.

Repair Priority for Used Equipment: Before replacing expensive controllers, thoroughly address harness wear, connector condition, and ground integrity—these account for the majority of E-17 faults in used PC220-7 excavators and require minimal investment compared to ECM replacement.

---

Disclaimer: This guide provides general troubleshooting information for experienced technicians. Always consult the official Komatsu service manual for your specific serial number range and consider professional diagnostic services for complex electrical issues. Improper repairs may cause additional system damage.