Park button will not work; car pops into neutral while driving

Wow, that sucks. Sorry to hear about this. There have been a couple of people mention popping into neutral but they didn't mention the check hybrid system indicator.
From doing modifications, I know if the shifter connector (inside center console) is not properly seated (or even connected), I would get the check hybrid system indicator. Perhaps it is a bad shifter(connections)?
Get that dealer to look at it again. Ask for the Customer Service Rep. at the dealer and let them know what is going on.
Welcome aboard by the way!

 

Welcome to another SE NC owner

What Spiderman said!

Just curious as what Toyota dealership you are dealing with in the area? Since the dealership could not duplicate the problem it is good that you could video it so you can show them. Unless they can duplicate the event or the car triggers a DTC (diagnostic trouble code) there is not much they can do about it.

Good luck this time.

 

Since you aren't getting codes, it's most likely a faulty shifter switch. If it makes intermittent contact, to the Prius it will be exactly the same as you manually shifting. If you can't demonstrate it to the dealer in person, take a video of it and show the dealer.

Tom

 

Sounds like a bad (shorted) Park switch. Any chance of a water spill around that area?

 

It may have not failed at the dealer, their version of drive it 100 miles is with the front weels spinning on some roller, like in a smog test, thats not real road driving, you may need to have them in the car with you and show it fails then.

 

Check the fuses, I remember reading someone on the forum was installing a camera in his c and the Park button stopped working. Turned out he blew a fuse.

 

Looks more and more like a bad switch. If I were the dealer tech the first thing I would do is to take it out and do continuity checks on it and if it fails replace it. Should not be rocket science.

 

Janine, even if you did press Park while driving down the road, it isn't supposed to actually engage the parking mechanism. You could even select Reverse while driving forward, and it still shouldn't allow you to damage the car or "transmission." I agree, it sounds like a loose connector or a bad selector switch/mechanism on the shift selector.

Too bad everyone in this thread who has replaced their shift selector is mostly in the Western region, or you could borrow their old selector that they took out to test if yours has gone bad:

Stage 10 Electronic Shifter available now | PriusChat

Perhaps you can use the pics and videos posted in the thread to at least check the connector on the shift mechanism to see if it is loose.

 

Any news Janine?

 

Very similar issue. Prius 2009.

Never had a problem with it, never skipped regular maintenance at the dealer since purchase, never a glitch.
Today, driving on a freeway, the master warning sign and engine malfunction light suddenly came up.

I stopped, called the dealer (service was closed) and was told that "if the car does not show other signs of obvious malfunction, like a coolant temperature alarm, it's probably a glitch related to emission issues" and that I could keep driving.

So I kept on driving (with those two indicator lights still on), back to the freeway, at 60miles/hour. Within 10miles the from where I had stopped, the VSC indicator also came up and then the security brake indicator popped up with a continued beep (the brake was obviously not engaged...) and the car popped itself into neutral. I could not put the selector back to "D", and all I could was pull over.

I pulled over, stopped the engine, restarted it. Only the general warning and the engine malfunction indicator were again on, went back to driving and within a mile, it happened again: Brake sign, beep, and car pops into neutral.

I had to have it towed.

After the car was back in my driveway, I turned the car back on. No alarm indicator lit up whatsoever. I drove about 3 miles on surface roads (30-40mph). Nothing happened, all seemed fine.

Going to the dealer for service tomorrow. Hopefully they figure out what's going on.
It is no fun to have a car switch irreversibly to neutral when you're on a freeway...

 

In the absence of user error, the affected folks should file a safety complaint at Home | Safercar -- National Highway Traffic Safety Administration (NHTSA).

Fbo, I'd have probably found a Gen 2 thread or started one there. Your 09 is not a Gen 3. I highly doubt the shifter parts are at all the same between the two given the know looks different and the Gen 3 mechanism feels flimsier to me.

 

Thanks cwerdna, will do.

I was pulled in this thread because the problem (in its weirdness) seemed similar, despite the different model. Perhaps, the fact that it does happen in different models could be a clue to what might be causing it.

In any case, if I don't find a similar Gen 2 thread, I'll probably open one tomorrow to report what the service dept. at Toyota will say about it. Those interested can look it up there.

-fbo

 

^^^
If the engine malfunction indicator light came up, there should be codes. Be sure to post what your DTCs were.

 

Been to service dept at dealer.

The only DTC code they found was for low voltage. They replaced the battery and said that all the alarm lights that I described could have been related to this problem, including the brake indicator + continued beeping sound. The only thing that, they say, it could not have been caused by it is the car going into neutral by itself. They controlled the shifter and determined it is not worn out. They had no explanation for the spontaneous shift into neutral and claimed that there is nothing they are aware of other than a faulty shifter that could lead to such a situation.

The car hasn't had any issue since, but needless to say I am not sure all problems have been identified and solved. Will see.

 

^^^
Do you have the DTC? Can you get it? We're flying almost totally blind w/o it.

 

The DTC was C1241. The auxiliary battery positive voltage was 9.9V (vs. 12V, so pretty dead).

The most frustrating part of the story was that, after replacing the battery, almost the exact same problem (warning lights and all, except for the shifting into neutral part) occurred again and this time the faulty part was found to be the hybrid inverter pump (DTC P0A93, if I recall well).

With a little more research on the topic, I found a post that is strikingly similar to mine:

Auxiliary Battery Failure | PriusChat

To me, there seems to be almost zero probability that this same sequence of events (low voltage on the AUX, followed by inverter pump failure) happens twice in nearly identical fashion and the two events are uncorrelated. The mechanics at the Toyota service point I went to were of different opinion...

In any case, I was told the AUX battery on GenIIs has an expected lifetime of 3 years.

-fbo

 

This morning on my way to work, after driving it twice for <10' in the early am, my 2007 Prius would not stay in drive, popping into neutral & not responding to the Park button. After repeated attempts to drive on surface streets by holding the "shifter" in Drive, I returned home late for work & took my husband's car. No signal lights illuminate when this occurs & later in the morning, my husband could not repeat the problem.

Toyota service did not return calls.

This car has experience an additional electrical anomaly, wherein it will turn on without the dashboard lights and then will not shut off at all. I have had to leave it running in my driveway or at work (the keys will not come out) for about an hour before it can be turned off. Any correlation between the two problems?

 

^^^
I've heard of your first issue before.

As for the latter, try pressing and holding power for a few seconds if it happens again. Also see Luscious Garage | Blog | LG TV - Prius Dead Dashboard and Combination Meter Warranty Enhancement | PriusChat.

You also may have a dying 12 volt. Please run the test at Weird stuff happening? MPGs dropping? Test The Battery | PriusChat after the car has sat MANY hours or overnight. Please tell us the 3 values (not just 1). Don't go changing the battery first until you tell us the values...

If you have HIDs, you can avoid unnecessary cycles on the lights by toggling between off and parking light positions.

Weird stuff can start happening w/a low or bad 12 volt. Don't waste $ on having a dealer "test" the 12 volt (07 Prius Dead - Any Guesses? | PriusChat). If you're on you're original 12 volt, it's likely near or at end of life now.