Sumitomo SH240-5 Fault Code 87: Complete Diagnostic Guide

What is Sumitomo SH240-5 Fault Code 87?

Fault Code 87 on the Sumitomo SH240-5 excavator indicates a malfunction in the pump control solenoid circuit, specifically related to the main hydraulic pump's electronic proportional control system. This code is triggered when the ECM (Engine Control Module) detects an abnormal voltage or current signal from the pump control solenoid valve that regulates hydraulic flow and pressure.

This fault is critical because the SH240-5 relies on precise electronic control of its variable displacement piston pumps. When Code 87 appears, the excavator's load-sensing hydraulic system cannot properly adjust pump output to match operational demands, directly impacting machine performance and fuel efficiency.

Common Symptoms

When Code 87 is active on your SH240-5, operators typically experience:

• Warning light illumination on the instrument cluster with potential audible alarm
• Loss of hydraulic power or sluggish boom, arm, and bucket movements
• Erratic hydraulic response where the machine operates normally intermittently before power loss returns
• Engine RPM fluctuation under load as the pump cannot properly communicate flow requirements
• Derate mode activation where maximum engine speed is limited to protect the hydraulic system

Potential Causes

The most common technical reasons for Code 87 on used SH240-5 excavators include:

• Pump control solenoid valve failure due to internal coil degradation or contaminated hydraulic oil causing spool sticking
• Wiring harness damage at the known rub point near the main pump mounting bracket where vibration causes insulation wear
• Connector corrosion at the 6-pin pump solenoid connector, especially on machines operated in wet or coastal environments
• ECM output driver circuit failure within the controller itself (less common but occurs in high-hour machines)
• Low voltage supply to the solenoid due to corroded ground connections or aging battery cables
• Hydraulic contamination causing the proportional valve to bind or respond incorrectly

How to Troubleshoot and Fix Code 87

Step 1: Visual Inspection Begin by inspecting the pump control solenoid wiring harness from the ECM to the main pump. On used SH240-5 excavators, check the harness routing near the hydraulic tank and pump mounting area for abrasion, cuts, or signs of previous repairs. Disconnect the 6-pin connector and inspect for corrosion, bent pins, or moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, measure solenoid resistance. The pump control solenoid should read between 8-12 ohms at room temperature. Next, check for voltage supply at the connector with the ignition on (should read approximately 12V). Perform a ground continuity test by measuring resistance between the solenoid ground pin and chassis ground (should be less than 1 ohm).

Step 3: Dynamic Testing If electrical values are correct, connect Sumitomo diagnostic software (or compatible equipment like Deere Service Advisor with appropriate adapters) to command the solenoid through various duty cycles. Monitor actual versus commanded current draw. A discrepancy indicates internal solenoid failure. For used machines, also check hydraulic oil condition—contaminated oil often causes premature solenoid valve failure.

Step 4: Component Replacement Replace the pump control solenoid valve if electrical testing confirms failure. When working on used excavators, always apply dielectric grease to connectors during reassembly and secure harnesses away from vibration points using new zip ties or protective loom. Clear codes and perform a hydraulic system calibration using diagnostic software.

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Disclaimer: This guide provides general troubleshooting information. Hydraulic systems operate under extreme pressure. Always consult your Sumitomo service manual and consider professional diagnostic assistance for complex electrical or hydraulic repairs, especially on used equipment with unknown service history.