Sumitomo SH220LC-5 Fault Code 1345: Complete Diagnostic Guide

What is Sumitomo SH220LC-5 Fault Code 1345?

Fault Code 1345 on the Sumitomo SH220LC-5 excavator indicates a Swing Motor Solenoid Valve Circuit malfunction, specifically detecting an abnormal electrical signal or open/short circuit in the swing motor control system. This code is generated when the ECM (Engine Control Module) detects voltage irregularities outside the normal operating range (typically 0.5-4.5V) in the swing motor's proportional solenoid valve circuit.

This fault is critical because the swing motor solenoid valve regulates hydraulic flow to the excavator's upper structure rotation. When this circuit malfunctions, the ECM may limit swing speed or disable swing function entirely to prevent hydraulic system damage. On used SH220LC-5 models, this code frequently appears due to age-related connector corrosion and wire harness deterioration near the swing motor mounting area.

Common Symptoms

• Swing function completely disabled or operates only at reduced speed regardless of joystick input
• Intermittent swing operation that cuts in and out during rotation cycles
• Warning light illuminated on the instrument panel with possible audible alarm
• Erratic swing response where the upper structure jerks or hesitates during rotation
• ECM derate mode activated, limiting other hydraulic functions to protect the system

Potential Causes

Electrical connector corrosion at the swing motor solenoid valve—extremely common on used machines exposed to moisture and debris accumulation around the center joint area.

Wire harness chafing where the swing motor cables pass through the center joint rotating assembly, causing intermittent shorts to ground.

Failed swing motor solenoid valve coil, with internal resistance outside specifications (typically should measure 8-12 ohms).

ECM internal driver circuit failure, though less common than field-level electrical issues.

Damaged wiring from previous repairs, aftermarket modifications, or rodent damage in the harness routing near the swing bearing.

Voltage supply issues from corroded ground connections at the swing motor mounting bracket.

How to Troubleshoot and Fix Code 1345

Step 1: Visual Inspection Disconnect battery power and thoroughly inspect the swing motor solenoid valve connector for corrosion, bent pins, or moisture intrusion. On used SH220LC-5 excavators, remove the connector boot and check for green corrosion—clean with electrical contact cleaner and dielectric grease. Inspect the entire wire harness from the ECM through the center joint to the swing motor for abrasion, especially where cables contact metal edges.

Step 2: Electrical Testing Using a digital multimeter, measure solenoid coil resistance at the valve connector (disconnected). Specifications should be 8-12 ohms; readings outside this range indicate coil failure. Check for voltage supply at the connector with ignition on—should read battery voltage (12-14V). Test for shorts to ground by measuring resistance between each solenoid wire and chassis ground (should read infinite resistance/open circuit).

Step 3: Circuit Continuity Check Verify harness continuity from the ECM connector to the swing motor solenoid using wiring diagrams specific to the SH220LC-5. Pay special attention to the center joint pass-through area where wires flex during rotation—this is the most common failure point on used machines. Look for resistance readings above 0.5 ohms indicating partial breaks.

Step 4: Advanced Diagnosis If harness and solenoid test within specifications, use Sumitomo diagnostic software (or compatible scan tool) to monitor live solenoid command signals while operating swing function. Compare commanded versus actual values to identify ECM driver circuit failures. Check ECM ground connections and power supply circuits before condemning the controller.

Step 5: Repair and Verification Replace damaged components, ensuring all electrical connectors receive dielectric grease for corrosion protection. After repairs, clear fault codes, cycle the swing function through full rotation in both directions, and verify code does not return. On used equipment, consider replacing the entire swing motor harness if wires show significant age-related deterioration.

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Disclaimer: This guide provides general troubleshooting information for experienced diesel mechanics. Always consult the official Sumitomo service manual for your specific serial number and follow proper lockout/tagout procedures. If unfamiliar with hydraulic or electrical systems, consult a certified Sumitomo technician to avoid injury or equipment damage.