Prius lurching forward

No. Maybe you thought you were in park, and, instead, neutral without foot on brake? Just guessing.

 

I'm a little confused... you were pulled over in Park, then the ICE kicked on and the car lurched? So, there was transmission of power to the wheels even though the vehicle was in Park?

 

No transmission of power to the wheels or failure to have selected Park. The Park pawl has a little play built in (set in Park on a flat section, get out and rock the car forward and backward) which allows a little bit of movement when the car responds to the engine's rotational inertia as it spools up to drive the small motor/generator to charge the low traction battery.

This is normal.

If this is undesirable, then set the parking brake, too.

 

I've had this happen to me a few times as well. It's while I'm in PARK after the car has been running a few minutes with the air on, the ICE kicks on to recharge the low battery, and the car seems to lurch forward a bit. just enough to scare me. I'm usually on the phone, mapping out my next job on my GPS, or doing some paperwork for my job when it happens. I thought this was normal, but since I don't have my foot on the brake when it happens, it does make me nervous. I am usually on flat ground in a parking lot, and I don't think the wheels move, but If I was parked up close to another cars' bumper I worry that it might touch when my Prius lurches forward.

 

This has happened to me and I even brought it up to the Dealership.. the car doesn't actually move forward, but the dynamics of the ICE turning on make it, let's say, shudder a bit... it is a bit scary frankly. The difference is when you're in a regular ICE and starting the car, your foot is on the brake, but when the Prius is in park, not so.. it might move about an inch or so and settle back to where it was. Really no more than the car might move in a strong wind or if you leaned against it in park (the opposite direction of where it "settled" in park).

A good idea maybe to always use the e-brake when in Park.

 

When the engine starts the car body can rotate a little without actually translating forward or back. This can feel like a lurch. If you are going to be stopped for more than a moment shift to "P" and apply the brake or parking brake, and you won't feel these lurches.

 

This has happened to me several times as well, I was told it was normal and not to worry about it, so for now I will not really worry about it. It has only happened in the garage after I have put the car in P and I am sitting there doing something

 

I agree with Richard... I get the opportunity to drive a lot of different Prii... They all seem to get that little lurch feeling when the ICE kicks in while in park. I have had customers comment on it while sitting as I instruct them on nav and bluetooth operation. IMO it is a charecteristic of the car.

 

Normal, you feel it much less if your foot is on the brake or the park brake is set.

 

The car does move forward! Day one of ownership, we were all standing around looking at the car while it was on in park but parking brake not set. When the ICE came on, the car rolled forward about and inch and then bounced back to it's previous position. I know it actually rolled forward because I was looking at the wheels when it did this and they rotated forward and then back. Scared me to death for a second as I thought it was going for a drive by itself. I realize now that this is normal and do not get alarmed by it, but we set the brake whenever we are parked with ignition on just for peace of mind.

 

One way to help reduce this is not only set the park brake but load it up a little.
Set the parking brake firmly if you plan to leave the car running in park, then with the car in drive take your foot off the brake and allow the electric motor to pull the car forward against the park brake, now re-apply the foot brake and select park. when you take your foot off the brake the car will likely move back a little as the park pawl finds its place. Now there is already some forward force on the park pawl so there is less tendency for the whole car to move when the ICE starts.

 

Prescription: "P" plus parking brake. No point in taking useless risks with safety.

 

I was just about to post my own questions on this when I found this thread, so I'll refresh the issue.
The lurching issue recently started with my 08 with 20k. Same thing - while in park when the engine kicks in the car lurches forward a small amount. Freaks you out every single time because there is actual forward movement. I don't care how many times people say set the parking brake, because that's just stupid when standing, and not actually parked. If my wife runs into DD for coffee, I'm not setting the parking brake - because I shouldn't have to. Or perhaps I'm in the passenger side and she leaves powered on for heat or AC. In the past the car always gave that normal small vibration shudder when the engine kicked in, but now there is freaky forward movement which should not be normal under any circumstances.

I think I'll video this and mark on the pavement so I can measure the actual forward movement.

This is hilarious. Siting in a parked car in a parking lot, even if "on", should never be considered a safety risk.



So its been over a year since these posts - anyone have more of an answer.

 

As stated before, the movement comes from play in the parking pawl mechanism. The actual forward movement is small, just an inch or two. If you do some formal testing, make sure to post your methods and results.

Tom

 

There is no other "answer".

The Prius doesn't have an "automatic transmission", in the conventional sense. Because of the design of the PSD, the movement that has been described and complained about by many is "normal", and part of the design (the parking pawl has to have some play in it so that it doesn't bind).

So if you want to "stand" with the engine running, simply move your left foot allllll the waaaay over to the parking brake, and step on it. Releasing the parking brake is equally as "hard to do". Both operations probably take less than a second each.

Look at it this way: if you were driving a manual transmission vehicle, there would not be a "park" position. If you were "standing" as you say, but in a car with a manual transmission, you would put the car in neutral, take your foot off the clutch, and then either 1) hold your foot on the brake pedal, or 2) set the parking brake. I don't hear anyone complaining about having to do this with a manual transmission car. It's just part of the nature or design of a manual transmission.

Now note this: the Prius does not have an automatic transmission, nor does it have a manual transmission. It has something totally different. It only has a single "gear", in the sense that term is normally used in automobiles.

Because it has neither an automatic or manual transmission, it has its own particular idiosyncractic behaviors. Will the car jump two feet if the parking brake is not set? No. But if you don't want to feel any lurch when the ICE kicks in (due to the play in the parking pawl), then set the parking brake.

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Now the question comes up regarding your particular situation: could this behavior get worse as the car ages? Possible. Maybe the parking pawl develops a little more "slop". Or maybe there is something else going on with your particular car.

If you have it checked out by a Toyota service shop, and they claim that it's "normal", you're probably ok. I say that because dealership shops are always looking for ways to make more money, and if they thought for a moment that something was wrong and they could get reimbursed by Toyota for a warranty repair, they would probably jump on it!

 

mine does all sorts of crazy lurches when the engine comes on, probably because i drive it terribly. still runs great..but nonetheless, what you are experiencing sounds normal to me.

 

Absolutely correct. Forgetting to set the parking brake someday when you really needed it, because you were not in the habit of setting it all the time, that's a safety risk.

And if you don't want to feel the lurch, set the parking brake.

 

The Prius doesn't care whether you think its behavior is "stupid" or clever. It acts the way it does.

If you are bothered by the lurch, then set the parking brake hard, or sell the car. Otherwise, expect to feel the lurch each time the engine starts.