Is this a tranaxle issue?

The jerkiness you describe is probably the normal jerk of the engine starting. Remember the prius does not have a transmission in the conventional sense. No gears are engaged or disengaged.

The engine's speed with respect to the tires is controlled by a small balancing motor (MG1). MG1 can run forward to increase engine speed with respect to the road, or run backwards to decrease engine speed with respect to the road. This is how the prius varies the "gear ratio" of the engine. (But this means torque applied by then engine is constant. To compensate for this, the prius has a second larger motor (MG2) which provides torque.)

MG1 is also used as a generator to recharge the batteries as well as the starter motor. Since MG1 is used to compensate for engine motion, when the car is stopped, it must run backwards (as a generator) to prevent the car from moving forward if the engine is on.

But if the car is stopped and the engine is off, but you want to start the engine, MG1 has to do it. During the starting sequence, MG1 is too busy trying to crank the engine forward to be able to run backwards to compensate for engine motion. But as soon as the engine starts, MG1 reverses course and the engine motion is removed, but not before your car feels like it wants to go... and you get that characteristic jerk forward.

When the car is in motion, this jerkiness is not felt. This is because MG2 is torquing the car forward. To start the engine, MG1 only needs to prevent the engine from being kept still. (Like a push start for a manual transmission car.)

The light and error code is probably a faulty sensor. Which unfortunately may not be cheap to replace. Prius transmissions are not like auto transmissions of regular cars. They are very robust. As long as you maintain the car, it will last for many many years. That said, maybe have the transmission oil checked. It's not ATF, it's just a gear oil. But it should be changed every 60-70k miles. Now american prii have these annoying get your oil changed lights that the dealer can reset... being Canadian, we are fortunate enough not to have those... I have no idea if the error code and light has anything to do with one of those mileage alarms...

 

P3009 means an electrical leak detected somewhere in the high voltage system. I am not sure that it implies within the transaxle. would like to know the service history on the car, particularly resealing of the HV battery? That may not have been done for most 2003s. Any visible damage to the HV wiring, particularly under the car?

Aside, would like you to change the transaxle fluid including removing/cleaning the bottom pan.

Your startup hesitation does not necessarily sound like a symptom of problems. But you probably need to dig into that 'leak'.

 

I don't think you have anything to worry about as far as the transaxle is concerned. The power split device is rock solid and the reduction gears past that point is also solid in design. I don't know of anyone who has had to change one.

Tochatihu mentioned that your error code is a highvoltage leak. That's not a seriously expensive issue to fix in most cases. It usually means something is not properly grounded or insulated. But that being said, there can be a potential for shock hazard with this type of problem, so take it seriously and have it checked out. The good news is you don't have to fix the transaxle.

Remember much of the conventional ideas about transmissions on regular cars don't apply to the Prius...

 

Re: Is this a transaxle issue?

If you decide to keep the car, you'll need to get the maintenance manuals (especially volume 2 but volume 1 too.) They show up on Ebay from time to time but I paid $300 in 2005 to get hardcopy for mine. If this is your only car, you have another problem.

Any used car is not going to be terribly reliable and you need a backup ride, especially if you plan to "do it yourself." You also need to survey your resources: (1) place to work on it, (2) tools, and (3) parts and tools budget.

As Doug pointed out the 'short' could be anywhere. Without the manuals, it is difficult to isolate the systems and identify the problem area. Trying to fault isolate by swapping parts gets very expensive, very quickly.

Bob Wilson

 

I would not trust a regular transmission ship to install a prius transaxle. Regular transmissions have little in common with any part of the prius transmission. Their expertise is really of no use.

First of all you need to find a dealership you can trust, barring that go to several and get a few opinions. There are many things that can cause an issue with your car. If there is a mechanical problem with either the PSD or the reduction gear, then you should have it looked at. Same if it's MG1 or MG2 that's giving you the problem. (Which it might well be, given an electrical error code...)

Anyways, remember the Prius transmission is NOTHING like a regular car's transmission. Taking a Prius to a transmission shop is like taking a boy to see a gynecologist... while they may be experts at what they do, they are not the right experts...

 

Treiberg, as you are in central California, I suggest you consult with Art's Automotive or Luscious Garage (both in SF bay area) concerning your transaxle options. These are good indy shops that could do the work.

 

When it comes to how the engine forces are transmitted to from engine/motor to the wheel (the transmission), "unique" is an understatement.

I don't think if it was diagnosed as the transaxle, that you would want to fix it anywhere that is not experienced with replacing the transaxle of the prius. The design of the prius does mean that regular transmission specialists would have no idea what they are doing. It is literally that different. It would be like trying to learn Japanese with an English-Spanish dictionary. Anyways, it doesn't have to be done by Toyota, but it does have to be done by someone experienced with the Prius' drive system. Just as if you had a car with a belt CVT that you would go to a mechanic that has experience with them.

Plus, I would definitely make sure that it IS the transaxle. And also what part of the transaxle. It could be two separate parts: the power split device (PSD) which is a big planetary gear system or it could be the reduction gear system. Also it may not be mechanical at all. So have it checked out by someone that knows the prius.

Transmission failures in most cars are quite common, since gears engage and disengage. This action wears out the teeth in the gears and it is quite normal for most cars to need transmission work later on in its life. But the Prius' transmission system has no gears that ever disengage. So this type of wear just doesn't happen. So it would have to be other issues, such as not changing the transaxle fluid as needed. Or similarly some other unusual circumstance that results in problems with the PSD or the reduction gears.

Anyways, I would stop planning for if it was the transaxle at fault and get it checked out. The stuttering (what seems like a rough shift into gear) when stopped and the engine turns on is normal. The error code you are getting is not. But that doesn't mean you have mechanical tranaxle parts that need to be replaced. Get it checked out...

 

Well if it's the mechanical part of the transaxle, then fixing it now would mean you would not have issues in the future. And the only question is if you are willing to pay for the fix.

If it's the electronic part of the transaxle, it won't cost that much. But honestly it's probably over priced, since they know they got you...

It's really how much you want the car...

 

a used transaxle would work fine, and its pretty simple to install well from my perspective.

aside from the technical complexity of the transaxle everything else to install is simple.

the reason why normal transmission shops cannot do this replacement is the high voltage. There are 3 wires going to the transaxle from the inverter on the 01-03 prius these wires i believe carry 3 phase power to the motors, Since i have removed the inverter once, i can vouch that there is residiual power left in the system even after the service plug is removed, a normal transmission shop would risk a lot.

 

it is filled with type 4 trans fluid not gear oil