Sumitomo SH220LC-6 Fault Code 87: Complete Diagnostic Guide

What is Sumitomo SH220LC-6 Fault Code 87?

Fault Code 87 on the Sumitomo SH220LC-6 excavator indicates a malfunction in the engine oil pressure sensor circuit or abnormally low oil pressure detected by the Electronic Control Module (ECM). This diagnostic trouble code (DTC) triggers when the ECM receives voltage signals outside the acceptable range from the oil pressure sensor or when actual oil pressure falls below the manufacturer's minimum threshold during operation.

This code is critical for the SH220LC-6 because inadequate oil pressure monitoring can lead to catastrophic engine damage. The Isuzu engine powering this excavator relies on precise oil pressure feedback to protect internal components from friction and overheating. When Code 87 activates, the machine may enter derate mode or initiate automatic shutdown sequences to prevent engine seizure.

Common Symptoms

When Fault Code 87 is active, operators typically experience:

• Engine warning light illuminated on the instrument panel, often accompanied by an audible alarm
• Automatic engine shutdown after a brief warning period (typically 30-60 seconds)
• Reduced engine power or derate mode limiting RPM to protect the engine
• Oil pressure gauge reading abnormally low or fluctuating erratically
• Intermittent code activation during cold starts or under heavy load conditions

Potential Causes

The most common technical failures triggering Code 87 on used SH220LC-6 excavators include:

• Failed oil pressure sensor due to internal diaphragm deterioration or contamination buildup
• Damaged wiring harness at known rub points near the engine block or frame rails
• Corroded electrical connectors on the sensor pigtail, especially in machines operating in wet environments
• Low actual engine oil pressure caused by worn oil pump, clogged oil filter, or bearing wear
• ECM voltage supply issues affecting sensor circuit reference voltage (typically 5V)
• Contaminated engine oil creating sludge deposits that block oil galleries

How to Troubleshoot and Fix Code 87

Step 1: Visual Inspection Begin by checking actual engine oil level using the dipstick—low oil is the simplest cause. Inspect the oil pressure sensor (located on the engine block near the oil filter) for physical damage, oil leaks, or corroded connector pins. On used excavators, examine the wiring harness from sensor to ECM for chafing against metal surfaces or heat damage.

Step 2: Electrical Testing Using a digital multimeter, disconnect the oil pressure sensor and measure resistance across its terminals (typically 50-250 ohms depending on temperature). Check for 5-volt reference signal at the sensor connector with ignition on. Inspect connector pins for corrosion—a common issue on older machines—and apply dielectric grease after cleaning.

Step 3: Mechanical Verification Install a mechanical oil pressure gauge at the sensor port to verify actual oil pressure (should read 30-60 PSI at operating temperature). If pressure is adequate but Code 87 persists, replace the oil pressure sensor. If mechanical pressure is low, investigate the oil pump, filter restriction, or internal engine wear.

Step 4: Advanced Diagnostics Connect Sumitomo diagnostic software or compatible scan tool to monitor live oil pressure data and compare sensor voltage output (0.5-4.5V range). Clear codes and perform a dynamic test under load to confirm repair.

For used excavators, always check harness grounding points and ECM connections before replacing expensive components.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Sumitomo service manual and consider professional diagnosis for complex electrical or engine mechanical issues. Improper repairs may void warranties or cause equipment damage.