What is Case CX210C Fault Code 87?

Fault Code 87 on the Case CX210C excavator indicates a Hydraulic Pump Solenoid Circuit malfunction, specifically related to the main pump control system's electrical circuit. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal voltage or current reading in the solenoid that regulates hydraulic pump displacement and flow.

This code is critical because the hydraulic pump solenoid directly controls the machine's hydraulic output based on operator demand. When this circuit fails, the ECM cannot properly modulate pump performance, leading to reduced productivity, inefficient fuel consumption, and potential damage to hydraulic components. On used CX210C models, this fault often stems from electrical degradation rather than mechanical pump failure.

Common Symptoms

When Code 87 is active on your Case CX210C, operators typically experience:

• Reduced hydraulic power across all functions (boom, stick, bucket, and swing movements become sluggish)
• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Erratic hydraulic response where the machine alternates between normal and reduced power modes
• Engine derating in some cases, where the ECM limits RPM to protect the hydraulic system
• Intermittent operation that worsens with machine vibration or temperature changes

Potential Causes

The most common technical causes for Code 87 on used CX210C excavators include:

• Damaged wiring harness near the main pump area, where cables rub against the frame or hydraulic lines (known wear point on this model)
• Failed hydraulic pump solenoid due to internal coil breakdown or contamination from hydraulic fluid ingress
• Corroded or loose electrical connectors at the pump solenoid or ECM interface
• Short circuit or open circuit in the solenoid control wiring
• ECM internal fault (less common but possible on high-hour machines)
• Low battery voltage or poor ground connections affecting solenoid activation

How to Troubleshoot and Fix Code 87

Step 1: Visual Inspection Begin by inspecting the wiring harness running from the ECM to the hydraulic pump solenoid. On used CX210C machines, check for harness chafing where cables pass near the pump mounting bracket. Look for melted insulation, exposed wires, or oil-soaked connectors that indicate fluid contamination.

Step 2: Electrical Testing Using a digital multimeter, disconnect the solenoid connector and measure resistance across the solenoid coil terminals. The specification should be approximately 10-15 ohms (consult your service manual for exact values). Also check for voltage supply at the connector with the ignition on—you should see battery voltage (12V) on the power wire. Test for continuity between the solenoid ground and chassis ground.

Step 3: Connector and Ground Verification Clean all electrical connectors with contact cleaner and apply dielectric grease. Verify the ground connection at both the ECM and pump mounting points—corrosion here is common on used machines operating in harsh environments.

Step 4: Solenoid Replacement or ECM Diagnosis If resistance and voltage tests fail, replace the hydraulic pump solenoid. If electrical values are correct but the code persists, use Case dealer diagnostic software to perform active tests and verify ECM functionality. On high-hour used excavators, consider ECM reprogramming or replacement if internal faults are detected.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Case service manual for your specific machine serial number and seek professional assistance from certified heavy equipment technicians for complex electrical or hydraulic repairs.