Sticky stick shift, reverts to neutral

I recommend that, if your car is still under the 3 year / 36K mile warranty, that you wait until the problem is bad enough so that you can demonstrate it to the service writer. If that warranty has expired, just ask for the shift selector mechanism to be replaced at your expense.

http://priuschat.com/forums/gen-ii-...ing/65102-how-replace-2g-gearshift-lever.html
http://priuschat.com/forums/gen-ii-prius-main-forum/82181-jumping-neutral.html
http://priuschat.com/forums/gen-ii-...n/51649-randomly-mine-wont-stay-in-drive.html
http://priuschat.com/forums/gen-ii-prius-main-forum/64071-gear-shift-keeps-returning-n.html

 

http://priuschat.com/forums/gen-ii-...hooting/80393-car-does-not-stay-in-drive.html

 

The problem is electrical failure of the gear selector mechanism, which is basically a fancy switch with two sensors (shift and select) to detect shift position: R, N, D, or B. The select sensor keeps track of lateral direction and the shift sensor keeps track of longitudinal direction. Each sensor contains a Hall IC. A magnet slider is the means used so that the Hall IC can track the lever position.

I suppose that until the car is fixed, you should advise your wife of the problem and let her know that the workaround is to hold the gear selector in the desired position i.e., D.

 

The shifter mechanism is based on Hall-effect transducers. These are chips that change the voltage of their output based on how close a magnet is to them (strength of the magnetic field). The whole point is that it's completely solid-state, with no parts to wear or contacts to go bad.

There are two sensors, one which senses horizontal movement of the shifter (from the null position over to Neutral, Drive and Reverse) and one which senses vertical movement (down to Brake, or once across to the left-hand side, up to Reverse or down to Drive). What's happening with your car is that it's intermittently, wrongly, reporting that the shifter is moved across, and this is happening for long enough to actually shift into Neutral.

I've never heard of anyone reporting that the car constantly drops into Brake, which might happen with a problem with the vertical sensor.

I can't find any DTCs that report if the sensor is open-circuit or shorted, which are present for virtually every other sensor on the car (including things like the Park button). There's nothing at all in the service manual about correcting problems with it.

I'd start by disconnecting the wiring harness from the HV ECU to the shift lever and checking continuity along it, checking it's not damaged, checking there are no shorts between pins or shorts to ground. Then clean the connectors and reconnect. Most likely the cable can move a bit and either one of the contacts has worked its way out of the plug, or it's rubbed against something and one of the wires has worn through.

 

Mike,

Am I understanding you correctly that your doubt replacement of the gear selector mechanism itself is likely to solve the problem, except insofar as the plug is reseated ?

 

There have been cases where the shifter has failed mechanically. The important part about the switches being Hall Effect is that it's not likely they will fail, especially intermittently. If the unit is mechanically sound, connectors are the most suspect part of the chain.

Tom

 

Tom, I reported similar gear shift problems in the thread noted above, and received advice to change the gear shift selector. I haven't yet since the problems have not resurfaced, but now I am confused if the selector is the likely culprit.

Perhaps all I should do is clean and reset the plug(s), as a first step ?
And ... dumb question of the day: how do you clean a connector ?

 

In my case, the problem was mechanical, as the return spring was not working. However your problem seems to be electrical in nature.

You could try that because it is quick and easy to do. I doubt that will resolve the issue but no harm in trying.

Use rubbing alcohol, brake parts cleaner or electrical parts cleaner. You want to use a solvent that will not leave a residue.

 

Another poster just posted about the same problem. In his case the dealer was able to replicate the problem by running the heat inside the car. Once it got hot, the shifter failed.

If it is heat related, it may very well be one of the Hall Effect sensors.

Tom

 

Were you charged $95 for this visit?

I am not aware of a TSB on this subject.

 

Well, next time you bring the car back (if the failure doesn't become more solid) perhaps you might suggest the tech try a heat gun (i.e. hair dryer equivalent) on the shift selector mechanism.

 

I just posted in another thread on this. I'm thinking there is more going on than the cup under edge of accelerator. Twice over the last couple of months - once just a week ago - I'm on the freeway and car is going great, then I notice when taking my foot off the accelerator, that engine braking is engaged, i.e. the gearshift is in "B". Now I know I DID NOT put it in "B" but rather "D" when I started out.

And now I have this revert to "N" on the gearshift. I'm copying and pasting my other post here and hope someone will comment.

Thanks.

Other post:
"OK, I read a couple posts on Gear Shift switching back to neutral. Here is my situation.
Got in the car to return some movies and realized I left them on the table. Went back to the house, and right before I turned into the driveway, noticed a metal coffee cup had come out of the holder and the edge was up under the accelerator. I had been applying my brakes to slow for the turn into the driveway, then when I went to accelerate, nothing, then noticed the cup.
Removed the cup and stepped on the gas to go into the driveway. Nothing. Turned the car off, then back on and tried to put into drive, goes a tiny bit then slips back into neutral. Tried it in reverse, same thing, pops back into neutral.
I can hold the shift lever in position and the car moves. It's in the driveway now and will get towed to the Toyota dealer tomorrow. Obviously a problem with the shifter as a result of the "coffee cup" under the edge of the accelerator. And yes, I know it's dangerous, hubby used the car last on his visit home this weekend and apparently the coffee cup either got put down on the floorboard or was knocked out. I had no idea, and I bring it in the home when I'm done.....anyway.
So, hubby is out of work and money is tight. I will have to have the Toyota dealer fix this, but I don't want to get taken to the cleaners. Anyone here have any idea if the most likely cause was the spring talked about in other posts breaking, or a switch sticking or what. Seems like something got knocked or shifted out of adjustment. Does the accelerator have some type of cut off switch if something gets lodged under it?
Any info is appreciated as to what may be wrong and how much I should be prepared for?

BTW 2008 Prius, 76,000 miles, had the transaxle fluid changed at 67,000. Everything has been working fine till this.
Oh yeah, forgot to mention it is HOT today. I saw that was a factor in the other reports.

So, least possible thing wrong? Any info is appreciated as to what may be wrong and how much I should be prepared for?

Also, will it hurt to hold the lever in "D" and drive it vs. having it towed?"