Anyone ever had their car stuck in Neutral?

What Patrick said. Maybe it's time to escalate to Toyota regional support, and refer them to Priuschat if they'd like some more examples and suggestions for a cure. Copy the letter to the NHTSA just to jerk their chain a little.

 

Funny, I had this happen for the first time a couple days ago, then yesterday, during the first wave of REALLY hot weather here in Oklahoma when I broke out the A/C to stretch its legs.

When I took the car in, they read the computer monitoring system and said I had a 'low voltage error' with my 12V battery that accounts for the failure of the car to stay in drive or reverse and pop back to neutral.

Apparently all they had to do was completely recharge the battery (even said it didn't need to be replaced) and reset the error alert. According to them, I should be fine.

If not, I'll be sure and update here, but if anyone is still dealing with that problem, don't overlook the 12V! It's apparently more vital to running a Prius than I thought!

 

Good to know that your problem is not a bad lever which could be expensive to replace.

Yes there are many weird errors that may occur when the 12V battery is weak so we better check it from time to time. It is easy to do:
http://priuschat.com/forums/gen-ii-...out-switching-headlights-off.html#post1095046

Good luck!

 

In the Prius the difference between neutral, drive, reverse, and B mode is an electrical state. Nothing in the "gearbox/transmission"alters mechanically, the exception to this is park where the transmission is mechanically locked.

The transmission selector lever mechanism contains no mechanical switches. The switching devices are hall effect transistors ( transistors affected by magnetism ).

The transmission effects gear change ratios, neutral, and reverse by altering the speed or direction of the two electric motor generators contained within, not by engaging different gears. In neutral the motor generators are disconnected so that they cannot drive the car in any direction and are free to rotate if the engine is running and cannot generate electricity, or start the engine.

The engine will only run if it is already running when the car is put in neutral, as the electric motor generators cannot be powered to start it.

 

This implies that the reason for these cars jumping out of gear is related to the Hall Effect transistors deciding that someone had moved the lever, thus triggering whatever they would have done if the driver had moved the lever. How sensitive are these circuits, I wonder, to variations in temperature (most instances of failure were reported at extreme temperatures) or bus voltage (several were blamed on bad 12V batteries) or a combination?

 

Unfortunately it is not as simple as that. The gear change lever electronics pass on the request for a given action to the transmission ECU, this ECU then carries out the request by powering from or allowing power to be returned to the HV battery via the inverter dependent on the needs of the system request.

 

I've had this same problem repeatedly on my 2004 Prius, and think I've figured out the cause. I believe the cold weather causes the "shift" joystick mechanism to slow down so it snaps back to its rest position more slowly than normal. As a result, the computer interprets it as you holding it at the neutral position as it must pass by neutral to go to either reverse or drive.
My solution is to quickly force the joystick back to its rest position (marked by a dot) after putting into Reverse or Drive whenever this happens. Sometimes it takes a couples tries, but it will then stay in gear indefinitely. When the interior warms up, it returns to behaving normally. My searches for this problem on the Web only indicate it happens on older models (before 2007); Toyota may have changed the way the software works.

 

I just had this happen, and I took the unit out and cleaned the contacts to the sensors. The white sensor on the side had varnish buildup and that cleaned off easily with CRC Lectroa-Motive spray and a soft plastic rod. The other sensor in the interior of the box had a coating of grease on the PC board that came from the mechanism. I used the CRC spray again and a very soft child's toothbrush and GENTLY cleaned the board. It has worked flawlessly ever since. I suspect that the grease was causing a slight voltage discharge that shorted out the board BTW, it was a nice spring day here when this happened and temp was not an issue.

 

welcome and well done!