The Subaru XV equipped with the TR580 or TR690 Lineartronic CVT (Continuously Variable Transmission) relies on a set of solenoids to manage the hydraulic control system that governs gear ratios, clutch engagement, and other critical transmission functions. These solenoids play a pivotal role in ensuring smooth and efficient operation of the CVT.

Overview of CVT Solenoids in the TR580 and TR690

The solenoids in these CVTs are electronically controlled valves that regulate hydraulic pressure and flow within the transmission. They work in conjunction with the Transmission Control Module (TCM) to adjust the pulley ratios, engage clutches, and control torque delivery.

Types of Solenoids in the TR580 and TR690:

1. Shift Control Solenoids:
   • Control the adjustment of the CVT pulleys, enabling seamless ratio changes.
2. Line Pressure Control Solenoid:
   • Maintains optimal hydraulic pressure for efficient operation and durability.
3. Lock-Up Control Solenoid:
   • Manages the torque converter lock-up clutch to improve fuel efficiency and reduce slippage.
4. Brake or Forward Clutch Solenoid:
   • Engages the clutches to enable forward or reverse operation.

Symptoms of a Faulty Solenoid in the TR580 or TR690

A malfunctioning solenoid can significantly affect CVT performance, with symptoms such as:

1. Delayed or Erratic Acceleration:
   • Difficulty in maintaining a consistent speed or sluggish response during acceleration.
2. Shuddering or Vibrations:
   • Uneven power delivery due to improper hydraulic control.
3. Failure to Shift Properly:
   • The transmission may stay in a fixed ratio or fail to adjust to driving conditions.
4. Check Engine Light (CEL):
   • Fault codes related to solenoid operation, such as P0776 (pressure control solenoid stuck off/on).
5. Overheating or Reduced Efficiency:
   • Increased heat or poor fuel economy due to improper torque converter lock-up.

Diagnosing Solenoid Issues

1. Error Code Analysis:
   • Use an OBD-II scanner to retrieve fault codes related to solenoid or pressure issues.
2. Hydraulic Pressure Tests:
   • Measure the transmission’s hydraulic pressure to identify solenoid or valve block problems.
3. Electrical Tests:
   • Use a multimeter to check solenoid resistance and continuity. Typical resistance values should match the specifications in the repair manual.
4. Visual Inspection:
   • Check the solenoid connectors and wiring for damage or corrosion.

Replacing a Faulty Solenoid

If a solenoid in the TR580 or TR690 requires replacement, follow these general steps:

Tools Needed:

• OBD-II scanner, torque wrench, socket set, and CVT-compatible fluid.

Procedure:

1. Preparation:
   • Disconnect the battery and drain the CVT fluid.
2. Access the Valve Body:
   • Remove the transmission oil pan and filter to access the solenoids.
3. Remove the Faulty Solenoid:
   • Disconnect the wiring harness and unbolt the faulty solenoid.
4. Install the New Solenoid:
   • Bolt the replacement solenoid into place and reconnect the wiring harness.
5. Reassemble and Test:
   • Reinstall the transmission filter and oil pan, refill with Subaru-recommended CVT fluid, and test drive to ensure proper operation.

Preventive Maintenance for CVT Solenoids

• Regular Fluid Changes:
  • Use only Subaru-approved CVT fluid to maintain solenoid and transmission health.
• Keep the Transmission Cool:
  • Ensure the CVT cooler and cooling system are functioning properly to prevent overheating.
• Avoid Heavy Loads:
  • Prolonged towing or aggressive driving can strain the transmission and solenoids.

If you need specific details such as solenoid part numbers, torque specs, or diagrams for the TR580/TR690, let me know!