Why the Bobcat S205 Drops Out of High-Flow Mode

[MikePhua]

The Bobcat S205 and Its Hydraulic Capabilities
The Bobcat S205 skid-steer loader was introduced in the early 2000s as part of Bobcat’s 200 Series, offering a blend of compact dimensions and robust hydraulic performance. With a rated operating capacity of 2,050 pounds and a turbocharged diesel engine producing around 66 horsepower, the S205 quickly became a favorite among landscapers, contractors, and municipalities.
One of its standout features is the optional high-flow hydraulic system, which boosts auxiliary flow from the standard 16.9 gallons per minute to approximately 30.7 GPM at 3,300 psi. This upgrade allows the S205 to power demanding attachments such as cold planers, stump grinders, and snow blowers. However, some operators report that the machine intermittently kicks out of high-flow mode, disrupting productivity and raising questions about system reliability.
Understanding High-Flow Activation and Control
High-flow mode on the S205 is electronically controlled and activated via a switch inside the cab. When engaged, the system reroutes hydraulic flow through a dedicated high-flow circuit, increasing output to the front auxiliary couplers. The control logic is managed by the loader’s main controller, which monitors engine RPM, hydraulic temperature, and operator input.
Key terminology includes:

• Solenoid valve: An electrically actuated valve that opens the high-flow circuit
  
• Pressure relief valve: Protects the system from overpressure by diverting excess flow
  
• Hydraulic couplers: Connect the attachment to the loader’s auxiliary lines
  
• Load sense line: Communicates pressure demand to the pump controller
  

If any part of this system malfunctions or detects abnormal conditions, the controller may deactivate high-flow to protect the machine.
Common Causes of High-Flow Dropout
Several factors can trigger the S205 to exit high-flow mode:

• Electrical faults
  • Loose or corroded connectors at the solenoid or control panel
    
  • Faulty high-flow switch or intermittent wiring
    
  • Low voltage from a weak battery or failing alternator
    
• Hydraulic overheating
  • Extended use of high-demand attachments without adequate cooling
    
  • Blocked or dirty hydraulic cooler fins
    
  • Low fluid level or degraded hydraulic oil
    
• Pressure spikes or relief valve activation
  • Sudden changes in attachment load can trigger the relief valve
    
  • Worn or misadjusted relief valve may open prematurely
    
• Software or controller logic
  

• Fault codes stored in the loader’s ECU may disable high-flow
  
• Incompatibility with certain aftermarket attachments lacking proper feedback
  

In one documented case, a snow removal crew in Minnesota found their S205 repeatedly dropped out of high-flow while operating a snow blower. After inspecting the wiring harness, they discovered a cracked connector at the solenoid valve. Replacing the connector resolved the issue.
Diagnostic Steps and Field Solutions
To troubleshoot high-flow dropout:

• Check hydraulic fluid level and condition
  
• Inspect cooler fins and clean with compressed air
  
• Test solenoid voltage and continuity with a multimeter
  
• Scan the ECU for fault codes using Bobcat’s diagnostic tool
  
• Verify attachment compatibility and coupler engagement
  
• Monitor hydraulic temperature during operation
  

If no faults are found, consider replacing the high-flow solenoid or switch. Some technicians also install a manual override or bypass to test the circuit independently of the controller.
Preventive Measures and Operator Tips
To reduce high-flow interruptions:

• Warm up the hydraulic system before engaging high-flow
  
• Avoid sudden load changes or rapid cycling of attachment controls
  
• Clean and inspect electrical connectors monthly
  
• Use OEM-spec hydraulic fluid and filters
  
• Install auxiliary cooling fans for high-demand applications
  

Operators should also be trained to recognize early signs of dropout—such as reduced attachment speed or warning lights—and respond before full disengagement occurs.
Stories from the Field
A contractor in Colorado retrofitted his S205 with a forestry mulcher and noticed frequent high-flow dropout during dense brush clearing. After installing a larger hydraulic cooler and upgrading the battery, the issue disappeared. He now uses the machine for full-day mulching without interruption.
In another case, a municipality in Ontario found that aftermarket snow blowers lacked proper pressure feedback, causing the loader to misinterpret demand and shut off high-flow. Switching to a Bobcat-branded blower resolved the problem.
Conclusion
High-flow dropout in the Bobcat S205 is often a symptom of electrical, hydraulic, or control system imbalance. With proper diagnostics, preventive care, and attention to attachment compatibility, operators can restore reliable high-flow performance and keep productivity on track. In compact equipment, every gallon per minute counts—and keeping the flow steady means keeping the job moving.