Sumitomo SH360HD-6 Fault Code 118: Complete Diagnostic Guide

What is Sumitomo SH360HD-6 Fault Code 118?

Fault Code 118 on the Sumitomo SH360HD-6 excavator indicates an Engine Oil Pressure Sensor Circuit malfunction or abnormally low oil pressure signal to the Engine Control Module (ECM). This code triggers when the ECM detects voltage readings outside the normal operating range (typically 0.5-4.5V) from the oil pressure sensor circuit, or when actual oil pressure falls below critical thresholds during operation.

This fault is particularly critical for the SH360HD-6's engine protection system. The oil pressure sensor provides real-time data that prevents catastrophic engine damage by monitoring lubrication integrity. On used excavators, this code often appears due to sensor degradation, wiring harness damage from vibration, or actual mechanical oil pressure issues that develop over thousands of operating hours.

Common Symptoms

• Engine derate mode activated, limiting RPM to 1200-1500 to prevent damage
• Red warning light illuminated on the instrument cluster, often accompanied by audible alarm
• Engine auto-shutdown after 30-60 seconds if pressure remains critically low
• Erratic oil pressure gauge readings or gauge stuck at zero despite engine running
• Reduced hydraulic performance due to engine power limitations in protection mode

Potential Causes

Electrical Issues (Most Common in Used Machines):

• Damaged or corroded wiring harness near the engine block where vibration causes insulation wear
• Failed oil pressure sensor (typical lifespan 5,000-8,000 hours)
• Corroded connector pins at the sensor or ECM interface
• Chafed wires at harness routing points behind the engine mount

Mechanical Issues:

• Actual low engine oil pressure from worn oil pump
• Clogged oil filter restricting flow (common when maintenance intervals are extended)
• Low engine oil level or degraded oil viscosity
• Worn main/rod bearings causing pressure loss

How to Troubleshoot and Fix Code 118

Step 1: Visual Inspection Check engine oil level using the dipstick—verify oil is at proper level and not contaminated. Inspect the oil pressure sensor (located on the engine block near the oil filter housing) for physical damage, oil leaks, or corroded connectors. On used SH360HD-6 excavators, examine the wiring harness routing from sensor to ECM for abrasion points, particularly where it contacts frame rails.

Step 2: Electrical Testing Using a digital multimeter, disconnect the sensor and measure resistance across sensor terminals (should read 50-150 ohms at room temperature). Check supply voltage at the sensor connector with ignition on—should read approximately 5V. Test harness continuity from sensor connector to ECM pins, and check for shorts to ground (should read infinite resistance).

Step 3: Sensor and Oil System Verification If electrical tests pass, install a mechanical oil pressure gauge temporarily to verify actual oil pressure (should be 40-60 PSI at operating temperature and 1800 RPM). Replace the oil pressure sensor if mechanical pressure is normal but code persists. For used machines with 6,000+ hours, replace the oil filter and retest before condemning the sensor.

Step 4: Advanced Diagnostics Connect manufacturer-specific diagnostic software (Sumitomo diagnostic tool or compatible CANbus scanner) to read live oil pressure data and compare against mechanical gauge readings. Clear codes and monitor for recurrence during a 30-minute operational test under load.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual and consider professional diagnostic services for complex repairs. Improper diagnosis may lead to engine damage or safety hazards.