Komatsu PC110-7 Fault Code E-16: Complete Diagnostic Guide

What is Komatsu PC110-7 Fault Code E-16?

Fault Code E-16 on the Komatsu PC110-7 indicates a malfunction in the engine controller (ECM) power supply circuit or abnormal voltage detection. This code specifically signals that the electronic control module is detecting inconsistent voltage input, typically outside the normal operating range of 20-32 volts DC, which prevents the ECM from properly managing engine functions.

This fault is critical for the PC110-7 because the ECM controls fuel injection timing, governor response, and emission systems. When voltage irregularities occur, the machine may experience reduced performance or fail to start entirely. This code is particularly common in used excavators where electrical connections have degraded over years of vibration and exposure to harsh jobsite conditions.

Common Symptoms

Operators experiencing Code E-16 may notice:

• Engine fails to start or cranks but won't fire
• Warning light illuminated on the instrument cluster with diagnostic code displayed
• Intermittent power loss or engine stalling during operation
• Erratic gauge readings on the dashboard, including battery voltage fluctuations
• Engine operates in derate mode with limited RPM and reduced hydraulic power

Potential Causes

The most frequent causes of E-16 on used PC110-7 excavators include:

• Corroded or loose battery cable connections at terminals or ground points
• Failing alternator producing inconsistent charging voltage (common after 5,000+ hours)
• Damaged wiring harness between the alternator and ECM, especially at flex points near the engine mount
• Faulty ECM power relay located in the main fuse box under the operator's cab
• Deteriorated main ground strap connecting engine block to chassis frame
• Water intrusion in ECM connector pins causing intermittent contact

How to Troubleshoot and Fix Code E-16

Step 1: Verify Battery and Charging System Using a digital multimeter, check battery voltage with engine off (should read 12.4-12.8V) and with engine running at high idle (should read 27-29V for the 24V system). Inspect all battery cable connections for corrosion, ensuring terminals are tight and clean.

Step 2: Inspect Wiring Harness and Connectors Examine the main power harness running from the alternator to the ECM. On used PC110-7s, check for wire abrasion where the harness contacts the engine block or frame rails. Disconnect the ECM connector (15-pin white connector behind left-side panel) and inspect for green corrosion, bent pins, or moisture.

Step 3: Test Alternator Output and ECM Relay Perform an alternator load test using appropriate diagnostic equipment. Replace if output is below specification. Check the ECM power relay by swapping with an identical relay in the fuse panel to rule out relay failure.

Step 4: Ground Circuit Verification Measure resistance between engine block and chassis ground—should read less than 0.5 ohms. Clean and retighten the main ground strap connections, as corroded grounds are a leading cause of voltage irregularities in older machines.

For used excavators, always address connector corrosion and harness wear before replacing expensive components like the alternator or ECM.

---

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu service manual for your specific machine serial number and consider professional diagnostics for complex electrical issues.