Sumitomo SH220LC-6 Fault Code 45: Complete Diagnostic Guide

What is Sumitomo SH220LC-6 Fault Code 45?

Fault Code 45 on the Sumitomo SH220LC-6 excavator indicates a malfunction in the Engine Oil Pressure Sensor circuit or abnormally low engine oil pressure detected by the Electronic Control Module (ECM). This code triggers when the sensor signal falls outside the manufacturer's specified voltage range or when actual oil pressure drops below safe operating thresholds.

This fault is critical for the SH220LC-6's Isuzu engine protection system. The ECM continuously monitors oil pressure to prevent catastrophic engine damage from inadequate lubrication. When Code 45 activates, the machine may enter a protective derate mode to limit engine speed and prevent bearing failure, crankshaft scoring, or complete engine seizure.

Common Symptoms

When Code 45 is active on your SH220LC-6, operators typically experience:

• Oil pressure warning lamp illuminated on the instrument cluster (red oil can icon)
• Engine power reduction or automatic derate limiting RPM to 1200-1500 range
• Audible alarm sounding continuously from the cab
• Intermittent code triggering during cold starts or high operating temperatures
• Engine shutdown in severe cases where pressure drops critically low

Potential Causes

The most common technical causes for Code 45 on used SH220LC-6 excavators include:

• Failed oil pressure sensor (typically located on the engine block's left side near the oil filter housing)
• Wiring harness damage from rubbing against the hydraulic pump mounting bracket—a known wear point on this model
• Corroded or loose connector pins at the sensor plug due to water intrusion
• Low engine oil level or incorrect viscosity oil for operating conditions
• Worn oil pump or clogged oil pickup screen reducing actual pressure
• ECM voltage supply issues affecting sensor reference voltage (typically 5V)

How to Troubleshoot and Fix Code 45

Step 1: Visual Inspection Check engine oil level using the dipstick—ensure it's within the proper range and verify oil condition. On used excavators, inspect the sensor wiring harness from the ECM to the oil pressure sensor for abraded insulation, particularly where it passes near moving components or sharp edges.

Step 2: Sensor and Connector Testing Disconnect the oil pressure sensor connector and inspect for corrosion, bent pins, or moisture. Using a digital multimeter, measure sensor resistance (typically 50-150 ohms at room temperature) and compare against Sumitomo specifications. Check for reference voltage at the connector (should read approximately 5V with ignition on).

Step 3: Live Pressure Verification Install a mechanical oil pressure gauge into the sensor port to verify actual pressure. At normal operating temperature and 1500 RPM, pressure should read 280-420 kPa (40-60 PSI). If mechanical pressure is normal but the code persists, replace the sensor. If pressure is low, investigate the oil pump, relief valve, or internal engine wear.

Step 4: Harness Continuity Check Test wiring continuity from sensor to ECM pins and check for short circuits to ground. On high-hour used machines, replace any sections showing insulation damage rather than attempting repairs with electrical tape.

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Disclaimer: This guide provides general diagnostic information. Always consult the official Sumitomo service manual and consider professional technician assistance for complex repairs or if you're unfamiliar with electrical diagnostics.