What is John Deere E240LC Fault Code 000656.05?

Fault Code 000656.05 indicates an Auxiliary Hydraulic Control Valve Solenoid Circuit Failure (FMI 05 - Current Below Normal or Open Circuit) on the John Deere E240LC excavator. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects abnormally low current flow or an open circuit condition in the electrical pathway controlling the auxiliary hydraulic proportional solenoid valve.

This code specifically affects the excavator's auxiliary hydraulic system, which powers attachments like breakers, grapples, or shears. The proportional solenoid valve regulates hydraulic flow and pressure to these attachments based on operator input. When the ECM cannot maintain proper electrical communication with this solenoid due to insufficient current, the auxiliary hydraulic function becomes unreliable or completely inoperative. For the E240LC, this is critical because many operators rely on auxiliary circuits for specialized work applications, and electrical faults can lead to costly downtime and reduced jobsite productivity.

Common Symptoms

• Auxiliary hydraulic function intermittent or completely non-responsive when attempting to operate attachments
• Diagnostic warning light illuminated on the instrument cluster with fault code displayed on monitor
• Reduced hydraulic flow to auxiliary circuit even when control lever is fully engaged
• No electrical actuation sound (clicking) from the proportional solenoid valve during operation attempts
• Error message on display screen indicating hydraulic system malfunction or electrical fault

Potential Causes

The most common technical causes for Code 000656.05 on used E240LC excavators include:

• Damaged or corroded wiring harness connecting the ECM to the auxiliary solenoid valve, particularly at harness routing points near the boom cylinder or upper structure where flexing occurs
• Failed proportional solenoid coil with internal open circuit or broken windings (common in machines with high operating hours)
• Corroded or loose electrical connectors at the solenoid valve or intermediate harness connection points, especially on machines exposed to wet or corrosive environments
• Broken or chafed wires at known rub points where the harness contacts the excavator frame or hydraulic lines
• ECM internal driver circuit failure (less common but possible in higher-hour machines)
• Poor ground connection at the valve mounting location or chassis ground point

How to Troubleshoot and Fix Code 000656.05

Step 1: Visual Inspection of Harness and Connections Begin by thoroughly inspecting the wiring harness from the ECM to the auxiliary hydraulic proportional solenoid valve. On used excavators, pay special attention to harness routing near moving components, particularly where the harness crosses from the upper structure to the boom assembly. Look for abraded insulation, pinched wires, or evidence of harness contact with sharp edges. Inspect all electrical connectors for corrosion, bent pins, moisture intrusion, or loose connection. Clean connectors with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing with Multimeter Disconnect the solenoid valve connector and measure the coil resistance across the solenoid terminals using a quality digital multimeter. Typical resistance values for John Deere proportional solenoids range from 8-15 ohms (consult your service manual for exact specifications). An infinite resistance reading indicates an open circuit within the solenoid coil, requiring solenoid replacement. Next, check for continuity and resistance in the harness from the ECM connector to the solenoid connector with the circuit disconnected at both ends. Any reading above 5 ohms suggests damaged wiring.

Step 3: Power Supply and Ground Verification With the ignition on (engine off), measure voltage supply at the solenoid connector. You should see battery voltage (approximately 12-14V) on the power supply wire. If voltage is absent, trace back toward the ECM checking for blown fuses, relay failures, or harness breaks. Verify the ground circuit integrity by measuring resistance between the solenoid ground terminal and a known good chassis ground—it should read less than 1 ohm.

Step 4: Advanced Diagnostics with John Deere Service Advisor If basic electrical checks pass, connect John Deere Service Advisor diagnostic software to perform active tests. Command the ECM to energize the auxiliary solenoid while monitoring actual current draw. The software will display if the ECM is attempting to supply current and whether feedback confirms proper circuit operation. This helps isolate whether the fault lies in the ECM driver circuit or external components.

Step 5: Component Replacement and Verification For used excavators, if wiring and connections check out but the solenoid resistance is out of specification, replace the proportional solenoid valve assembly. When installing, ensure proper connector sealing and secure harness routing away from wear points using new zip ties or protective loom. After repairs, clear the fault code using diagnostic software, cycle the auxiliary hydraulics multiple times, and verify the code does not return.

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Disclaimer: This guide provides general troubleshooting information for Code 000656.05. Always consult the official John Deere service manual for your specific E240LC serial number and software version. If you lack proper diagnostic tools or experience with electrical systems, consult a certified John Deere technician to prevent further damage or safety hazards.