Kobelco SK135SR-2 Fault Code A245: Complete Diagnostic Guide

What is Kobelco SK135SR-2 Fault Code A245?

Fault Code A245 indicates a malfunction in the swing motor solenoid valve circuit, specifically detecting an abnormal electrical signal or open/short circuit condition in the swing motor control system. This code is logged by the machine's Electronic Control Module (ECM) when it detects voltage irregularities outside the normal operating range (typically 10-14V DC) in the swing motor's proportional solenoid valve wiring.

The swing motor system is critical for the SK135SR-2's operational efficiency, as it controls the upper structure rotation speed and precision. When this circuit fails, the excavator's ability to perform smooth, controlled swing operations is severely compromised, directly impacting productivity and potentially causing unsafe working conditions.

Common Symptoms

When Code A245 is active, operators typically experience:

• Intermittent or complete loss of swing function, with the upper structure failing to rotate or responding erratically to joystick commands
• Swing motor operates at reduced speed or exhibits jerky, unpredictable movement patterns
• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Swing function works in one direction only, indicating a directional solenoid valve failure
• Error code display on the multi-function monitor with potential entry into a derated operating mode

Potential Causes

The most common technical causes for A245 on used SK135SR-2 excavators include:

• Damaged wiring harness between the ECM and swing motor solenoid valve, particularly at known rub points near the center joint and swing bearing area
• Failed swing motor solenoid valve coil, often due to internal short circuits or coil breakage from vibration exposure over time
• Corroded or loose connector pins at the swing motor valve connector (common in machines with 5,000+ operating hours)
• ECM internal circuit failure affecting the solenoid driver circuit (less common but possible in high-hour machines)
• Voltage supply issues from the main power harness or blown fuses in the swing control circuit
• Moisture intrusion into the solenoid valve connector, especially in machines operated in wet conditions

How to Troubleshoot and Fix Code A245

Step 1: Visual Inspection Begin by inspecting the wiring harness routing from the ECM (located in the cab) to the swing motor solenoid valve assembly. On used excavators, pay particular attention to harness sections passing through the center joint area where repetitive swing motion causes wear. Check for abraded insulation, pinched wires, or evidence of previous repairs with electrical tape.

Step 2: Connector and Pin Testing Disconnect the solenoid valve connector and inspect for corrosion, bent pins, or moisture. Clean contacts with electrical contact cleaner and verify pin tension. Using a digital multimeter, measure resistance across the solenoid coil terminals—typical values should read between 8-15 ohms. Readings showing infinite resistance indicate an open coil; near-zero readings suggest a short circuit.

Step 3: Voltage Supply Verification With the ignition on but engine off, backprobe the connector to verify supply voltage at the power feed wire (typically 12V). Start the engine and confirm voltage remains stable under load. Voltage drops below 10V indicate upstream power supply issues requiring battery, alternator, or main harness investigation.

Step 4: Solenoid Valve Replacement or Repair If resistance and voltage tests confirm solenoid failure, replace the proportional solenoid valve assembly. For used machines, consider ordering OEM Kobelco parts (Part #YN35V00037F1 or equivalent) rather than aftermarket alternatives, as solenoid valve tolerances significantly affect swing precision. After replacement, clear fault codes using Kobelco diagnostic software (TCSS or compatible scan tool) and perform operational testing.

Step 5: ECM Circuit Testing If all external components test normal, the ECM's internal driver circuit may be faulty. This requires advanced diagnostics with the manufacturer's diagnostic software to monitor solenoid command signals versus actual current flow. ECM replacement or professional repair is necessary if internal faults are confirmed.

Used Equipment Consideration: Before replacing expensive components, thoroughly inspect all harness routing for damage from previous bucket or attachment strikes, which frequently damage center joint wiring on older SK135SR-2 units.

---

Disclaimer: This guide provides general diagnostic information for Code A245. Hydraulic and electrical systems operate under high pressure and voltage. Always consult the official Kobelco service manual for your specific machine serial number and consider professional diagnostic services for complex electrical issues. Improper repairs may void warranties or create safety hazards.