What is Kobelco SK135SR-2 Fault Code R014?

Fault Code R014 on the Kobelco SK135SR-2 excavator indicates a malfunction in the Rear Attachment Solenoid Control Valve circuit. This diagnostic trouble code (DTC) signals that the Electronic Control Module (ECM) has detected an abnormal electrical condition in the solenoid valve that controls hydraulic flow to rear-mounted attachments such as breakers, thumbs, or augers.

The R014 code specifically monitors the auxiliary hydraulic circuit's solenoid valve, which regulates pressurized oil flow to auxiliary attachment ports. When the ECM detects irregular voltage, abnormal resistance, or open/short circuits in the solenoid wiring harness, it triggers this fault. This is critical for the SK135SR-2 because improper solenoid function can cause hydraulic pressure imbalances, reduced attachment performance, or complete loss of auxiliary hydraulic control—directly impacting productivity on job sites.

Common Symptoms

When fault code R014 is active on your Kobelco SK135SR-2, operators typically experience:

• Illuminated warning light on the instrument cluster or diagnostic panel
• Complete loss of auxiliary hydraulic function—rear attachments won't operate despite switching activation
• Intermittent operation of auxiliary hydraulics that works sporadically or only in certain positions
• Hydraulic flow irregularities where attachment speed is inconsistent or weak
• ECM logging the fault even when auxiliary function appears temporarily normal

Potential Causes

Several technical issues commonly trigger R014 on used SK135SR-2 excavators:

• Damaged solenoid valve coil with internal short or open circuit (common failure point after 4,000+ operating hours)
• Corroded or loose electrical connectors at the solenoid valve—particularly vulnerable to moisture intrusion on used machines
• Wiring harness abrasion where the auxiliary circuit harness contacts the boom or stick (known rub point on this model)
• Failed solenoid valve internal components causing electrical feedback to the ECM
• ECM internal fault in the solenoid driver circuit (rare but possible on older units)
• Blown fuse or damaged relay in the auxiliary hydraulic control circuit
• Voltage supply issues from the main power distribution harness

How to Troubleshoot and Fix Code R014

Step 1: Visual Inspection and Preliminary Checks

Begin by visually inspecting the rear attachment solenoid valve located near the hydraulic pump assembly. Check all electrical connectors for corrosion, moisture, or loose pins—a major issue on used excavators exposed to harsh environments. Inspect the wiring harness routing from the cab controls to the solenoid valve, paying special attention to areas where the harness may contact moving components or sharp edges.

Step 2: Electrical Testing with Diagnostic Tools

Using a digital multimeter, measure resistance across the solenoid coil terminals (disconnect the harness first). The typical resistance should be 15-25 ohms for Kobelco solenoids; refer to your service manual for exact specifications. Next, check for voltage supply at the harness connector with the ignition on—you should see battery voltage (12-14V). Test for continuity in the ground circuit back to the ECM.

Step 3: Advanced Diagnostics and Component Testing

Connect Kobelco diagnostic software (or compatible heavy equipment scanner) to retrieve detailed fault data and check for additional codes. Perform a solenoid activation test through the diagnostic software to command the valve on/off while monitoring electrical response. If the solenoid tests faulty, replacement is necessary. For used excavators, thoroughly clean all connector pins with electrical contact cleaner and apply dielectric grease before reassembly to prevent future corrosion.

Step 4: Repair and Verification

Replace the solenoid valve if resistance or function tests fail, or repair damaged wiring harness sections using proper gauge wire and weatherproof connectors. After repairs, clear the fault code through the diagnostic interface and cycle the auxiliary hydraulic function multiple times. Monitor for code recurrence over several operating hours.

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Disclaimer: This guide provides general troubleshooting information for Kobelco SK135SR-2 fault code R014. Always consult your machine's official service manual and consider professional diagnosis by a certified Kobelco technician, especially for complex electrical or hydraulic system repairs. Improper repairs may void warranties or cause additional damage.