What is Sany General Fault Code P926?

Fault Code P926 indicates a malfunction in the auxiliary hydraulic pump solenoid circuit, specifically detecting an open circuit or abnormal voltage condition in the electrical pathway controlling the auxiliary hydraulic pump activation system. This code is triggered when the Electronic Control Module (ECM) detects that the commanded signal to the auxiliary hydraulic pump solenoid is not generating the expected response, typically due to interrupted current flow or improper resistance readings.

In Sany excavators, the auxiliary hydraulic system powers attachments like breakers, grapples, and shears. The solenoid valve controls hydraulic flow to these circuits based on operator input and ECM commands. When P926 activates, the ECM recognizes that electrical continuity has been compromised somewhere between the control module, the wiring harness, and the solenoid itself. This fault directly impacts attachment functionality and can reduce machine versatility on job sites where auxiliary tools are essential.

Common Symptoms

• Auxiliary hydraulic functions become completely inoperative or intermittently fail to activate when the operator engages attachment controls
• Warning light illumination on the instrument cluster, often accompanied by a wrench or system fault icon
• Error message display on the monitor screen specifically referencing hydraulic system or solenoid malfunction
• No hydraulic pressure reaching auxiliary attachment ports, rendering breakers, thumbs, or other tools unusable
• ECM may log multiple instances of the fault if the condition is intermittent due to vibration or connector movement

Potential Causes

Damaged or corroded wiring harness connections are the primary culprit in used excavators, particularly at connector points near the pump assembly where exposure to hydraulic fluid, dirt, and vibration is constant.

Failed auxiliary pump solenoid coil due to internal winding breakdown, especially common in machines with 3,000+ operating hours where thermal cycling degrades electrical components.

Broken or frayed wires in the harness routing between the ECM and solenoid valve, often occurring at stress points where the harness flexes during boom or arm movement.

ECM internal driver circuit failure, though less common, can prevent proper voltage output to the solenoid circuit.

Corroded ground connections that increase circuit resistance beyond acceptable parameters, triggering open-circuit detection.

How to Troubleshoot and Fix Code P926

Step 1: Visual Inspection Begin with a thorough examination of the wiring harness from the ECM to the auxiliary pump solenoid. On used excavators, focus on areas where the harness passes near moving components or sharp edges. Check all connector pins for corrosion, bent terminals, or hydraulic fluid contamination. Clean connectors with electrical contact cleaner and inspect for moisture intrusion.

Step 2: Electrical Testing Using a digital multimeter, disconnect the solenoid connector and measure resistance across the solenoid coil terminals. Typical specifications range from 8-15 ohms; consult your service manual for exact values. An infinite resistance reading confirms a failed solenoid. Next, check for supply voltage at the harness connector with the ignition on—you should see battery voltage (12-24V depending on system). If voltage is absent, trace back toward the ECM.

Step 3: Circuit Continuity Check With the harness disconnected at both ends, test continuity from the ECM connector to the solenoid connector for each wire in the circuit. Any open circuit indicates a break requiring harness repair or replacement. Pay special attention to ground circuit integrity, testing resistance from the solenoid ground to chassis ground (should be less than 1 ohm).

Step 4: Component Replacement and Verification If the solenoid tests faulty, replace it with OEM or high-quality aftermarket parts. For used machines, consider replacing associated connector pigtails simultaneously to prevent future corrosion issues. After repairs, clear the fault code using Sany diagnostic software or a compatible scan tool, then cycle the auxiliary hydraulic function multiple times while monitoring for code recurrence.

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Disclaimer: This guide provides general troubleshooting information. Always consult the manufacturer's service manual for your specific model and serial number. If you're unfamiliar with electrical diagnostics or hydraulic systems, seek assistance from a certified Sany technician to prevent injury or further equipment damage.