2004 Prius shifts self into neutral when steering wheel is turned to max

[Scottie_T]

Last week, I went out to my car in the morning with a slight frost on the windshield and the air very damp. I started the car up, shifted into reverse, and began to back out of my parking spot. As I turned the wheel to the max to finish exiting the spot, the car shifted itself into neutral and the wheel became hard to turn as if the power steering had died. Needless to say, this spooked me a bit, so I put it in drive to pull back into the spot. When I turned the wheel to the max in the other direction, the car again shifted into neutral. I put it back in drive and finished pulling into the spot. This played out once more as I backed out and then pulled into the spot again. I decided to try driving around my neighborhood to see what would happen. This time, I just kept shifting into reverse every time it shifted itself into neutral until I had cleared the car next to me and could drive forward. The car did not shift out of drive, so I drove off to work.

I haven't had this happen again, but I figured I'd post my experience on here in case anyone else has seen this (or will see it in the future). My inclination was that the environment was a factor. It was cold and damp, so perhaps the electronics were being affected negatively.

If you have any suggestions of things to test or things to ask my repair shop, I'd appreciate them.

[richard schumacher]

Well, that's a new one... In this case "repair shop" should be "Toyota dealer". Please tell us what they find.

Did anyone ever take apart the steering column or dash for any reason, or do any electrical work?

[JimboK]

There have been isolated reports of the gear shift mechanism failing, though I've seen none reporting an association with steering wheel position. Could still be the same underlying problem, I suppose: either debris in the shifter or outright failure. See these threads for more, both discussions of other failures, with the second including instructions for a DIY fix:

knob costs $700 to replace?

How to Replace 2G Gearshift Lever

[Spartane]

I don't know if the electric steering assist is driven from the 12V battery or not, but if it is then perhaps going to the lock position caused a higher load on the battery than normal, forcing the voltage to droop.

Weird, unpredictable things have been reported when the 12V battery is about to die and this might be one of them.

[Spartane]

Here's a link that shows you how to test your 12V battery:
What has the cold weather done to my beautiful Prius?

[qbee42]

The steering on the Prius is electrically assisted. When turned to the limit, it produces a higher load on the 12v bus. If your 12v system is marginal, it could cause all sorts of weird problems.

First thing you should check is your 12v battery and connections.

Tom

[hobbit]

Yup, 12V would be my vote too, 'specially given the model year.
But you should make sure your DC/DC charging system is working
right too, as it should have held up the EPS load and all the
rest if the car was in READY.
.
_H*

[Sandy]

12V I went through hell looking for the gremlins.... they were in the 12V