Troubleshooting Loss of High Travel Speed on the Fiat-Hitachi EX215 Excavator

[MikePhua]

The Fiat-Hitachi EX215 is a reliable hydraulic excavator favored for general earthmoving, excavation, and construction tasks. One common operational issue owners face is the loss of high-speed travel function. When the machine fails to shift into high travel mode, productivity suffers—especially on large job sites requiring frequent repositioning. This detailed article explores potential causes, diagnostic steps, and solutions for resolving high-speed travel failures on the EX215, with real-world insights and terminology explanations for clarity.
Understanding the High-Speed Travel System
The Fiat-Hitachi EX215 features a two-speed travel system: a standard low gear for digging and fine maneuvering, and a high-speed gear for efficient relocation across longer distances. The transition between travel speeds is electronically or hydraulically controlled depending on the model and configuration.
The operator activates high travel via a switch or foot pedal. When working correctly, the system signals the travel motors to shift from low to high displacement mode, increasing ground speed without increasing engine RPM. This mode is dependent on several conditions being met.
Key Components Involved in High Travel

• Travel Speed Solenoid Valve: Actuates the switch between low and high travel modes.
  
• Travel Motors: Equipped with two-speed functions (low/high displacement swash plates).
  
• Travel Speed Selector Switch: Operator-controlled input, located on the console or floor pedal.
  
• Pilot Control System: Delivers low-pressure hydraulic signals to command valve changes.
  
• Machine Control Logic: Determines if conditions are safe for high-speed mode (e.g., hydraulic load, slope, boom position).
  
• Sensors and Wiring: Detect pedal position, travel direction, and hydraulic state.
  

Common Causes of Lost High-Speed Travel

• Faulty Travel Speed Solenoid: If the solenoid is damaged, stuck, or unplugged, the valve may not shift to high-speed mode.
  
• Broken or Disconnected Wiring: Worn harnesses or corroded connectors can break the signal between the switch and the valve.
  
• Defective Travel Switch or Pedal Sensor: If the operator input is not registered, the command never reaches the system.
  
• Pilot Pressure Loss: If pilot hydraulic pressure is low or absent, the signal to shift the travel motors may never reach the actuators.
  
• Mechanical Failure in Travel Motor: Internal failure in the swash plate mechanism may prevent the travel motor from physically shifting to high mode.
  
• ECU Logic Lockout: The machine's electronic control unit may restrict high-speed travel under certain load conditions or fault scenarios.
  

Diagnostic Procedure

1. Initial Functional Check
   • Confirm that the high travel switch or pedal is functioning and lights up (if applicable).
     
   • Attempt to engage high travel on flat, unloaded terrain with boom and arm in neutral.
     
2. Electrical Testing
   • Use a multimeter to test continuity at the travel speed switch.
     
   • Check voltage at the solenoid coil while pressing the switch or pedal.
     
   • Inspect all related fuses and relays for continuity.
     
3. Solenoid Inspection
   • Manually activate the travel solenoid by supplying power to it directly.
     
   • Listen for an audible “click,” indicating valve movement.
     
   • Remove and clean the solenoid to eliminate internal contamination.
     
4. Pilot Pressure Verification
   • Use a pressure gauge on the pilot circuit to confirm pilot pressure is reaching the travel valve.
     
   • Check for blocked pilot lines or stuck pilot valve spools.
     
5. Travel Motor Analysis
   • Jack up the machine and observe travel motors while attempting high travel.
     
   • Compare the left and right motors’ response—symmetrical behavior confirms motor-side health.
     
   • Investigate further if one motor remains sluggish or unresponsive.
     
6. Control Logic Review
   • Check the machine’s diagnostic screen (if equipped) for any stored fault codes.
     
   • Look for logic lockouts: boom elevated, arm engaged, swing motion, or grade sensors detecting slope.
     

Terminology Explanation

• Pilot Pressure: Low-pressure hydraulic signal used to control high-pressure valves and actuators.
  
• Solenoid Valve: Electrically controlled valve that opens or closes fluid flow paths based on switch input.
  
• Swash Plate: An internal mechanism in hydraulic motors that adjusts displacement and thus controls motor speed.
  
• Two-Speed Travel: System allowing the operator to switch between high and low gear modes in excavators.
  
• Load Lockout: A safety feature that disables certain functions if the machine is in an unsafe or loaded state.
  

Real-World Case Examples
In one instance, a contractor reported that their EX215 had no high travel, causing significant delays moving between excavation points. Diagnostic work found that the solenoid connector had come loose due to vibration and dust ingress. Cleaning the contacts and reseating the plug restored full function.
Another mechanic described a case where only one track would switch to high-speed mode, leading to lopsided tracking. The cause was traced to a broken wire leading to the right-side travel motor solenoid, which was fixed by replacing a section of the wiring harness.
A third case involved a false lockout from the machine logic. A sensor on the boom incorrectly reported it being elevated, preventing the system from allowing high travel. After recalibrating the sensor, the issue was resolved.
Preventive Maintenance Suggestions

• Regularly inspect solenoid connectors for corrosion, tightness, and wear.
  
• Test pilot pressures during scheduled services.
  
• Clean hydraulic filters and pilot line strainers to prevent pressure drop.
  
• Keep operator stations and foot pedals clean to avoid mechanical binding.
  
• Use dielectric grease on connectors to improve electrical reliability.
  

Summary List of Troubleshooting Tips

• Check travel speed switch and verify function.
  
• Inspect and test travel solenoid for power and operation.
  
• Test pilot pressure to ensure control signal is reaching valves.
  
• Examine travel motors for mechanical function or internal failure.
  
• Use diagnostic display or logic diagrams to rule out lockout conditions.
  
• Inspect and repair any damaged or corroded wiring in the travel circuit.
  
• Don’t overlook sensor faults or boom position warnings that can prevent shifting.
  

Conclusion
Losing high-speed travel on the Fiat-Hitachi EX215 is a manageable but multifactorial issue, requiring a methodical approach to diagnose and fix. By understanding the interdependent roles of pilot hydraulics, electrical controls, and machine logic, technicians can restore full mobility and performance. Through preventive maintenance and awareness of common failure points, many high-travel issues can be prevented before they impact productivity on the job site.