One problem related to steering pinion shaft has been reported for the 2012 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Toyota Highlander based on all problems reported for the 2012 Highlander.
Making popping noise in steering wheel when turning. Took to dealership where I have it serviced and they informed me it was the steering shaft assembly. Which cost $273 dollars before labor. My understanding is that they have had problems with the 2008 to 2013 models. In my opinion this is a safety issue and should be covered by Toyota.