Gen4 no power- how can you put in neutral?

maybe a blown fuse?

 

They're going to have to dolly it. All four wheels off the ground.

 

If its only front wheel drive (not all wheel drive) it has to be towed with the front wheels lifted off the ground. The tow truck operator should know that.

 

And parking brake released.

2012 plug-in will not be AWD.

 

You can’t.

 

In a lot of cars (even including the first-generation Prius), there is an ignition key cylinder on the steering column, and when the key is turned off the steering is locked. That serves a mandated theft-protection purpose.

Prius starting with gen 2 has a non-locking steering column. You can always turn the steering. To serve the mandated theft-protection purpose instead, the transmission is moved in and out of Park by an electric motor, which is mounted in a hard-to-reach place on the transmission, and it is a kind of motor that you can't even just hotwire by sticking two wires on a battery. It is a kind of motor that only moves when current is sent to its three sets of windings in the right kind of sequence, which is done by the Transmission Control ECU, which has got to have 12-volt power, and it communicates with the ECUs that recognize your key code, and will only shift into neutral if it is convinced you have powered up the car, using a recognized key.

I'm not sure what you meant by "Gen 3 had options." This has been the Prius anti-theft measure going clear back to gen 2.

If you are not able to provide 12-volt power and a recognized key, your options are pretty limited. You could build yourself a box of electronics producing the right output sequence to spin a switched-reluctance motor, and patch it into the wires to the Park actuator motor, and "hotwire" it that way. Or you could remove the motor from the transmission and use a big screwdriver or the like to shift the linkage inside.

Maybe that got a little easier with gen 3 because gen 2 had the actuator motor on the firewall side of the transmission in a place nearly impossible to reach, while gen 3 moved it to the front. But the gen 3 one is still held on with tamper-resist covers over the mounting bolts. There is, intentionally, no easy way to get the car out of Park without having power and the proper key.

Having the tow driver put dollies under the wheels is generally going to be easier than any way of trying to defeat that.

 

the easiest option for any of them is a jump pack, or cables. no big deal, unless the 12v isn't the problem, then you have a bigger deal

 

There really is no true "neutral." The drivetrain has no disengagement from the electric motor and gasoline engine.
It's a simulated neutral, achieved by the computer, to deliver no torque to the wheels, regardless of which motor/engine is running or if the car is in motion.

The towtruck driver should know that a dolly under the front wheels is how you tow a Prius.

 

Paul has posted this kind of thing before. If anything, it is more accurate to describe the transmission as always in neutral (or Park, when it's mechanically locked), requiring the computer to 'simulate' all non-Neutral behavior.

Because MG1 is a free element inside the transmission, when there are no currents flowing in the stator windings to interact with it, it freely spins and there is negligible torque passed from the engine to the wheels or vice versa.

The thing that gets in your way trying to move the car without 12-volt power is simply the Park-locking mechanism and the (intentional) difficulty of retracting it without 12-volt power and the correct key.

Get the Park linkage retracted and you can go ahead and power the car back down if you want (if you unplug the Park motor first so the automatic return to Park on power-down can't happen), and the car, needing no power, rolls around pretty much like any other car you ever pushed around in neutral.

You have to lean a little extra hard to start it moving, because this capacitor is normally at 0V when the car's off, and your initial shove puts a charge on it from MG1:



It's not all that big a capacitor, so your first shove brings it pretty quickly to a voltage matching MG1's, at which point current flow ceases and the car's no harder to push around than any like-sized car in neutral.

 

If you were able to disable the parking pawl, the car may possibly move when towed, but the gearing from the drive wheels to MG1 is a very high ratio, so it seems unlikely. If it does turn, the electric motor (brushless, therefore not dragless) would be spinning at a very high speed without adequate lubrication, which would be a bad idea..

Your belief that there is no computer-assisted rotation of the electric motor while in "neutral" seems to lack plausibility. At any rate, if it were designed that way, it would be a poor design.

 

What seems unlikely? That it would move? The car's easy to put in neutral and push, so that's easy to check.

You seem to like saying things like "very high ratio" and "very high speed"; let's go ahead and use some numbers, the way people do who are genuinely interested in understanding something.

If I've got the right published figure (3.947) for the Prime final drive ratio, then that times the 78/30 PSD ratio to MG1 means that MG1 will spin at 3.947*78/30 = about 10.26 times the RPM of the wheels. Whether such a ratio deserves a label like "very high" might be a judgment call.

We're posting in a thread about somebody wanting to get the car in neutral because a tow truck showed up. There could be two reasons the OP is asking:

1. I want the car in neutral so we can push it from where it is to where the tow truck can hitch on and tow with the front wheels lifted (the recommended way, on p. 550 of the owners' manual). Or:
2. I want the car in neutral so it can be towed with all wheels on the ground (the 'emergency' way, on p. 552), at the recommended speed of under 18 mph (30 km/h).

For (1), it's hardly worth calculating what "very high speed" MG1 will reach while the car is pushed by hand across the driveway.

So let's take (2), and use the maximum recommended speed of 18 mph, and use 770 as the tire revs per mile. That's a wheel speed of 231 rpm, or an MG1 speed of 2370 rpm. That's a small fraction of MG1's rated rpm, and its drag at 2370 rpm (when there is no winding current flowing to create any electromagnetic effect) is like spinning any other small flywheel in a set of decent bearings. Peanuts.

That is a point, and probably one of the reasons Toyota preferentially recommends towing with the front wheels up. But notice it's an entirely separate issue from whether any kind of powered 'simulation' is needed for the car to roll in neutral.

What it lacks in plausibility-to-Paul-Gregory it makes up in factuality, which to me is the more interesting metric.

Far be it from me to say you could never come up with a better one, but you could probably improve those odds even more by making sure you understand theirs first.

 

Of course the car must be running for that to happen. It's easy to push the car when the computer is calculating zero torque to the wheels. Happens in the car wash all the time.

Do you know how a brushless motor works? The Prius uses rare earth magnets strong enough to break your arm. The resistance to being rotated through the gearing ratio from pushing it, makes it absurd and impossible.

 

No, the car must be unparked for that to happen. It is a matter of only moments to put the car IG-ON, shift to neutral, unplug the park actuator from the transmission control ECU so it can't return to Park again, and power the car off. Then, if you somehow don't trust that the car is off when it's off, take off the battery cables if you want.

Then push the car. It's as easy as that.

The instructions for doing that were in post #12—the exact one you replied to in #13.

But here you are not only pretending not to have seen a post you replied to a couple hours ago. You're also pretending not to have seen the one from our conversation in February on the same subject. (And, of course, this isn't the first time you've pretended not to have seen that.)

Mirabile dictu, I do.

 

You seem obsessed over this issue. You're saying what would happen if you do this and that...
Where's the evidence?

 

No, I'm saying what did happen when I did this and that. In my lexicon, that's kind of what 'evidence' means.

The reason I give the details of how to do it is just so, if there's anybody else around who wonders if I just made it up, they know how to reproduce what I did.

There's a pretty long tradition of evidence being presented that way, and over the years it has worked pretty well.

 

I'd need some documentation to believe it.

 

I think OP's been towed by now?