What is Sany Excavator Fault Code P165?

Fault Code P165 on Sany excavators indicates a malfunction in the hydraulic pump solenoid circuit, specifically detecting an abnormal electrical signal or open/short circuit condition in the pump control system. This diagnostic trouble code (DTC) is generated when the Electronic Control Module (ECM) detects voltage irregularities outside the manufacturer's specified range (typically 9-16V on Sany systems) within the proportional solenoid valve circuit that regulates hydraulic pump displacement.

This code is critical because the hydraulic pump solenoid directly controls engine load matching and hydraulic flow distribution. When P165 triggers, the excavator's ability to optimize fuel efficiency and coordinate engine speed with hydraulic demand becomes severely compromised, potentially leading to overheating, reduced productivity, and accelerated component wear.

Common Symptoms

• Reduced hydraulic power across all functions (boom, arm, bucket, swing) with noticeably slower cycle times
• Engine RPM fluctuations or failure to automatically adjust under varying loads
• Hydraulic system overheating due to improper pump displacement control
• Warning lamp illumination on the instrument cluster (typically a wrench or engine icon)
• Erratic or jerky movements during combined hydraulic operations

Potential Causes

The most common technical causes for Code P165 on used Sany excavators include:

• Damaged wiring harness near the hydraulic pump mounting area where vibration causes insulation wear and wire exposure
• Failed proportional solenoid valve within the pump assembly due to internal coil breakdown (common after 5,000+ operating hours)
• Corroded electrical connectors at the pump solenoid plug, especially on machines operated in wet or coastal environments
• ECM internal fault or poor ground connection at the controller mounting bracket
• Voltage supply issues from the main power harness or faulty relay feeding the solenoid circuit

How to Troubleshoot and Fix Code P165

Step 1: Visual Inspection Begin by thoroughly inspecting the wiring harness running from the ECM to the hydraulic pump. On used excavators, check for harness routing against sharp edges, evidence of rubbing near the pump mount, or connector corrosion. Clean all connections with electrical contact cleaner and verify pin integrity.

Step 2: Electrical Testing Using a digital multimeter, measure resistance across the solenoid coil terminals (disconnect harness first). Sany specifications typically require 8-15 ohms; readings outside this range indicate coil failure. Check for supply voltage at the connector with ignition on—should read battery voltage. Test for continuity to ground, as any reading below 10k ohms suggests a short circuit.

Step 3: Component Testing If electrical values are correct, perform a functional test using Sany diagnostic software (PC-E or equivalent). Command the solenoid through various duty cycles while monitoring amperage draw. Replace the proportional solenoid valve if it fails to respond or draws excessive current (>2.5A). For used machines, always inspect the connector pins for heat discoloration indicating previous intermittent faults.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Sany service manual for your specific model and serial number. Complex electrical diagnostics should be performed by certified technicians with proper diagnostic equipment.