Komatsu PC210-10 Fault Code E-35: Technical Guide

What is Komatsu PC210-10 Fault Code E-35?

Fault Code E-35 on the Komatsu PC210-10 indicates a Regeneration Switch Circuit malfunction in the Diesel Particulate Filter (DPF) system. This code specifically signals that the Engine Control Module (ECM) has detected an abnormal voltage or open/short circuit in the wiring harness connected to the manual regeneration switch.

This code is critical for the PC210-10 because the DPF regeneration system directly impacts exhaust emissions compliance and engine performance. When the regeneration switch circuit fails, operators cannot manually initiate DPF cleaning cycles, leading to excessive particulate buildup, potential engine derate, and costly DPF replacement if left unaddressed.

Common Symptoms

When Code E-35 is active on your Komatsu PC210-10, you may experience:

• DPF warning light illuminated on the instrument cluster (amber or red depending on severity)
• Inability to activate manual regeneration mode using the dashboard switch
• Intermittent error messages on the monitor panel regarding DPF system malfunction
• Progressive engine power loss or derate mode if regeneration cycles cannot complete
• Abnormally high exhaust backpressure readings during diagnostic checks

Potential Causes

The most common technical causes for E-35 in used PC210-10 excavators include:

• Faulty regeneration switch assembly due to worn contacts or internal component failure
• Open or short circuit in the wiring harness between the switch and ECM (common at harness routing points near the battery box)
• Corroded or loose connector pins at the switch plug or ECM connector—especially in machines with 3,000+ operating hours
• Damaged wiring insulation from rubbing against cab mounting brackets or hydraulic lines
• ECM internal circuit failure (rare, but possible in high-hour used machines)
• Water intrusion into the switch housing from damaged cab seals or pressure washing

How to Troubleshoot and Fix Code E-35

Step 1: Visual Inspection Begin by locating the regeneration switch on the operator's control panel (typically marked with a DPF icon). Inspect the switch housing for physical damage, cracks, or moisture. Check all visible wiring from the switch through the cab harness for chafing, cuts, or corrosion—pay special attention to the harness routing near the cab floor plate where rubbing commonly occurs on used machines.

Step 2: Electrical Testing Using a digital multimeter, disconnect the switch connector and measure resistance across the switch terminals while activating the button. You should read continuity (0-5 ohms) when pressed, and open circuit (OL) when released. If readings are inconsistent or show infinite resistance when pressed, replace the switch assembly.

Step 3: Harness and Voltage Verification With the ignition key ON (engine off), backprobe the harness connector at the switch. Measure supply voltage—you should see approximately 12-14 volts on the power supply wire. Check for ground continuity (less than 1 ohm to chassis ground) on the ground wire. If voltage is absent or ground is poor, trace wiring back to the ECM connector and check for damaged pins or loose connections.

Step 4: ECM Communication Check Connect Komatsu KOMTRAX or compatible diagnostic software to verify the ECM is receiving switch input signals. Monitor live data while pressing the regeneration button—the ECM should register a status change. If wiring and switch test good but the ECM shows no response, inspect the ECM connector C401 (common failure point) for corrosion or backed-out pins.

For Used Excavators: Before replacing components, thoroughly clean all connector terminals with electrical contact cleaner and apply dielectric grease to prevent future corrosion. Inspect harness routing and secure any loose sections with proper cable ties to prevent future chafing damage.

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Disclaimer: This guide provides general troubleshooting information for Code E-35. Always consult the official Komatsu PC210-10 service manual and certified technicians for machine-specific repairs. Improper diagnostics may cause additional damage or void equipment warranties.