RAV4 Power steering fail

[bigcar]

Hi,

Wonder if anyone can help.  a week ago our RAV4 (2006 XT4 6DR2.2; 90k miles) suddenly lost power steering while manoevering at slow speed. Unlike other posts I have read on several forums, there were no other fault lights displayed. The local garage had been working on the car the day before, replacing a faulty starter motor (which was under warranty as it had already been replaced about a year ago; I mention this as the electrical failure may be relevant? Battery is relatively new, 18 months old). The garage owner came and collected the car and drove it - without power steering- the half mile back to the garage. Just as he pulled in, the power steering started to work again. The garage was unable to find a fault, and said there were no error codes. Since then we have driven the car a few times - reluctantly - but no recurrence. Very nervous about driving it in case it happens again. Any ideas on root cause, items to check or thoughts on likleyhood of repeat occurrence?

[gjnorthall]

Sudden failure of electronic power steering is far more common than you'd think and invariably happens when manoeuvring slowly. What is really unusual is that you didn't get a warning light or code - though some steering motor problems result in communication issues with the steering module. Stating the obvious perhaps - does the warning light illuminate when switching on the ignition? - and does your garage have the equipment to read steering system codes? In terms of the latter, I've seen garages attempting to read steering  codes with an engine diagnostic tool via the OBD socket and they then incorrectly conclude that no codes means no codes from any system. The power steering system is very susceptible to system voltage and often power steering can be knocked out when connecting / disconnecting the Battery or pulling / fitting fuses - in your case it would be difficult to link to the previous days events since the steering was OK in the intervening period.

Unfortunately without a fault code it's very laborious to fully check out the system - it's a lot easier when the system is in the failed mode. If the system has been thoroughly checked out - there's little more that can be done. The failure may have been associated with some transient condition but there is no guarantee that it won't repeat. Driving without power assistance is perfectly safe but is not a pleasant experience. The AA generally won't transport cars with failed electronic steering - after checking the car, they will advise drivers to drive carefully to the nearest dealers.