What is Sany Excavator Fault Code P795?

Fault Code P795 indicates a malfunction in the hydraulic pump solenoid valve circuit, specifically detecting an abnormal electrical signal or open/short circuit condition in the pump control system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects voltage irregularities outside the normal operating range for the hydraulic pump's proportional solenoid valve.

In Sany excavators, the hydraulic pump solenoid valve regulates pump displacement and flow rate based on operator demand and engine load. When the ECM cannot properly communicate with or control this solenoid, hydraulic performance becomes compromised. This fault is critical because it directly affects the machine's ability to modulate hydraulic power, impacting all functions from boom movement to swing operations. The pump control circuit operates typically between 12-24V DC, and any deviation triggers this code to protect the hydraulic system from damage.

Common Symptoms

• Reduced hydraulic power across all functions, with noticeably slower cycle times for boom, arm, and bucket operations
• Engine derating or failure to reach maximum RPM under load conditions
• Warning light illumination on the instrument cluster, often accompanied by an audible alarm
• Erratic hydraulic response where functions may work intermittently or feel "sluggish" during operation
• Increased fuel consumption as the engine compensates for inefficient hydraulic performance

Potential Causes

The most common technical causes for Code P795 in used Sany excavators include:

• Damaged wiring harness near the hydraulic pump mounting area where vibration and heat cause insulation breakdown
• Corroded or loose connector pins at the solenoid valve plug, especially in machines exposed to moisture or muddy conditions
• Failed proportional solenoid valve due to internal coil breakdown or mechanical sticking from contaminated hydraulic fluid
• ECM internal fault or corrupted software requiring reprogramming or module replacement
• Voltage supply issues from the main power harness, including poor grounds or damaged relay contacts
• Hydraulic fluid contamination causing the solenoid spool to stick, creating abnormal current draw

How to Troubleshoot and Fix Code P795

Step 1: Visual Inspection and Connector Check Begin by locating the hydraulic pump solenoid valve on the main pump assembly. Disconnect the electrical connector and inspect for corrosion, bent pins, or moisture intrusion. On used excavators, check the wiring harness routing for rub points against the frame or pump housing—this is a common failure point. Clean connectors with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing with Multimeter With the connector disconnected and ignition off, measure resistance across the solenoid coil terminals. Typical specifications range from 8-15 ohms; consult your service manual for exact values. Next, check for voltage supply at the harness connector with ignition on—you should see battery voltage (12-24V). Test for continuity to ground on the ground circuit wire. Any open circuits or resistance outside specifications indicate wiring faults.

Step 3: Advanced Diagnostics with Scan Tool Connect Sany-compatible diagnostic software to monitor real-time solenoid command values and actual current draw. Command the solenoid through various test cycles while observing amperage—excessive current suggests internal solenoid failure, while no current draw indicates open circuits. Check for ECM output capability by testing adjacent solenoid circuits for comparison.

Step 4: Component Replacement and Verification If testing confirms solenoid failure, replace the proportional valve assembly with OEM or quality aftermarket parts. For used machines, simultaneously replace the connector pigtail if corrosion was present. After installation, clear codes, perform hydraulic system bleeding, and conduct operational testing under load. Verify proper pump displacement response through diagnostic software.

---

Disclaimer: This guide provides general troubleshooting information for educational purposes. Hydraulic and electrical systems operate under high pressure and voltage. Always consult the manufacturer's service manual and consider professional assistance from certified Sany technicians for complex repairs, especially on used equipment where undocumented modifications may exist.