The Highlander has been assigned 817 TSBs over 20 model years.
TSBs contain recommended steps and procedures for diagnosing or repairing a known problem. They are issued directly by Toyota to service technicians. You'll often see TSBs used as evidence in lawsuits when owners feel the automaker should help with repairs.
A TSB can cover multiple models and years. The 2014 Highlander has been involved in the most campaigns with 327 total service bulletins.