What is Sany Excavator Fault Code P605?

Fault Code P605 indicates a malfunction in the hydraulic pump solenoid proportional valve circuit, specifically detecting an abnormal current or voltage signal within the main pump control system. This code is triggered when the Electronic Control Module (ECM) detects that the electrical current flowing through the proportional solenoid valve is outside the manufacturer's specified range, typically between 0-1000 milliamps depending on load demand.

In Sany excavators, the proportional valve precisely controls hydraulic pump displacement by regulating flow based on operator input and system pressure. When this circuit malfunctions, the ECM cannot properly modulate pump output, directly impacting machine performance and fuel efficiency. This is particularly critical in used machines where electrical connections and solenoid coils deteriorate over time from heat cycles and vibration.

Common Symptoms

• Reduced hydraulic power across all functions, with noticeably sluggish boom, arm, or swing movements
• Engine over-revving without corresponding hydraulic response due to improper pump load matching
• Intermittent or constant warning light on the instrument cluster, often accompanied by a wrench icon
• Erratic hydraulic response where functions suddenly lose power or operate inconsistently
• Increased fuel consumption as the engine works harder to compensate for inefficient pump control

Potential Causes

The most frequent causes of P605 in used Sany excavators include:

• Solenoid coil failure due to internal winding breakdown from prolonged heat exposure (resistance typically measures 3-7 ohms when healthy)
• Corroded or loose connector pins at the pump solenoid harness, especially where the cable passes near the hydraulic pump mounting area
• Chafed wiring harness rubbing against the pump housing or engine block—a known wear point on machines with 3,000+ operating hours
• Failed ECM driver circuit unable to supply proper voltage to the proportional valve
• Contaminated hydraulic oil causing the solenoid spool to stick, increasing electrical resistance

How to Troubleshoot and Fix Code P605

Step 1: Connect Sany diagnostic software or a compatible multimeter to measure solenoid resistance. Disconnect the solenoid connector and measure across the coil terminals—readings outside 3-7 ohms indicate coil failure requiring replacement.

Step 2: Inspect the wiring harness from the ECM to the pump solenoid. On used excavators, carefully check where the harness routes near moving components or sharp edges. Look for abraded insulation, corroded pins, or moisture in connectors. Clean connections with electrical contact cleaner and apply dielectric grease.

Step 3: With the ignition on (engine off), use a multimeter to verify the ECM is supplying proper voltage (typically 12-24V) to the solenoid circuit. If voltage is absent, suspect ECM issues or a blown fuse in the control circuit.

Step 4: Check hydraulic oil quality and filter condition, as contaminated oil can cause mechanical binding of the solenoid spool, creating electrical load anomalies.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Sany service manual and consider professional diagnostic assistance for complex electrical or hydraulic system repairs.