Electric power steering


I read your 6/1/08 column in the Washington POst and was interested in your response to Rebecca on the failure of the electric power steering in her 2003 Prius. I recently read a sales brochure for the 2009 Toyota Corolla, and it features electric power steering, presumably adapted from the Prius. I am unable to see just how the unit works but I expect that it, like hydraulic power steering would have some relief protection if it tries to go beyond steering lock. Rebecca said that she “used all my might” to straighten the wheels. I suspect she would say the same if driving a hydraulic steering unit whose engine drive belt had broken. Why would the eletrical failure in her car entail such damage to the rack and pinion that it has to be replaced?


In 2001-2003 Prius, the electrical power steering failed because of noisy potentiometers on the torque sensor. Toyota replaced many under warranty, but not all, apparently.

2004 model onwards, Hall Effect sensors were used instead, with much better reliability. If this comes in the 2009 Corolla I would expect that to also use Hall Effect.

I was looking around for a thread about Rebecca’s, so I could mention another potential source for the steering systems; salvage vehicle dismantlers.