2003 Honda Odyssey P0730 Code: Shift Control System Fault Diagnosis & Repair Options

My 2003 Honda Odyssey suddenly developed a check engine light several months ago. After scanning at Autozone, the diagnostic code returned as P0730 — indicating a problem in the shift control system. The symptom is that occasionally, during normal daily commutes (about 10 miles one way), the vehicle locks into gear 2 and will not allow shifting. Pressing the accelerator only increases RPM without any movement. After approximately half to three seconds, the issue resolves automatically. Based on forum research, possible causes include: 1) Internal blockage in the transmission main control; 2) Faulty shift solenoids or wiring; 3) Failure of the transmission control module (TCM). I'm unsure whether further diagnostic testing is necessary to pinpoint the exact issue. Should I take it to a Honda dealership, or would an independent repair shop suffice? Given that this may involve only electrical components like solenoids, replacing just those parts could be significantly cheaper than full transmission replacement — which can cost between $2,000 and $3,000. Alternatively, some shops offer salvaged transmissions at lower prices, but I'm concerned about reliability and long-term performance. Any advice on the best course of action for diagnosing or repairing this P0730 issue would be greatly appreciated.