Is there a forum specifically for this issue: The gas engine in my 2005 Prius comes on in the garage even when the battery shows almost fully charged and I haven't stepped on accelerator. And I think that engine kicks in too soon when I'm driving gently down the street. I will be bringing Prius in for its 10,000 mile servicing in a few weeks. I called the dealer and was told NO ADJUSTMENTS TO THE COMPUTER ARE POSSIBLE!! Does anyone know if this is completely true? Is there some way to get them to adjust it? Can I do it myself? How do I know if its working "normally"?
The gas engine will come on and shut off when and where the car wants it to. When you start the car, whether the battery is fully green or not, the engine still needs to warm up, even if only for a few seconds. Especially if you have anything on in the car that might use up juice-climate control, audio, light, etc. This is how the Prius is supposed to function, there's nothing wrong with the car whatsoever and I wouldn't worry. Short of self-installing an EV mod to the car, there's not a lot you can do about it. Maybe look into that if it interests you...
Can't be totally sure if your Prius is working normally, but I suspect it is. There are many factors that would cause the engine to start, aside from the battery needing charge. By the way, unless you have an EV switch, your engine will always start about ten seconds after turning the car on. This is totally normal. It's also much easier to keep the engine from starting while driving gently if you have an EV switch and put it in this mode... but still, it takes a very light touch to prevent the ICE from starting. Rick S
Another thing to add is the Prius will start the ICE immediately if you have the front defrost on. I'm pretty good at making sure it's off when I stop the car so I can engage EV mode on the next startup.
Since you failed to mention your location, I am assuming you live in a colder climate. If so, just wait till the weather warms up and your problem will solve itself.
no adjustments like that are possible. the ECU program is a complete unit and cannot be tweaked to user preference. the car works to provide good fuel economy AND low emissions. the "low emissions" part is what's bugging you. but the car does what it has to do to warm up the engine and the cat in a timely fashion for emissions. nothing you can do about it. in short, they're not lying to you.
THANKS A LOT TO EVERYONE FOR YOUR PROMPT AND USEFUL RESPONSES. It never occured to me that warming up the engine and the catalytic converter would explain the early startup I''ve noticed. ABOUT THE EV SWITCH: is this something that I would have to install myself? does Toyota not provide or install it? would it invalidate my Toyota warrantee? Thanks again, Roger G
Search on "EV switch" and you'll find the many answers to your questions. It is one of the most popular topics here, along with running out of gas (sheesh). By the way, I've never seen an "adjustable computer." Well, I guess a slide rule qualifies...
It's important to understand the Prius is not an electric vehicle. In fact, ALL of the motive power comes from the ICE! The battery and electrics are there only to assist the engine make the best use of its torque and fuel efficiency. When you take off from a stop, the ICE will turn on. It's the prime mover and it is needed to add its power to the wheels. In fact, the best fuel efficiency comes when the engine drives the wheels directly. Any time the electric motor is used, you are losing efficiency from the losses generating, storing, and using the electricity. The Prius is a gas powered car. The electrics merely help it run in its most efficient range. Don't try to drive on the electric motor all the time!
The car can definitely be adjusted. Mine is completely different since the SSC50P update. Before I had trouble staying electric. Now it is easy and I can do it even on some hills where it never happened before. Every computer update has tweaked things a bit differently from what I read hear. Only problem is we don't get to choose which update to get!
The electric motors are always being used. At all times when the engine is running, 40% of its torque goes to MG1. At low speeds this translates to a large percentage of the engine's power; at high speeds, it translates to a low percentage. What you really mean to say is that you lose efficiency when energy flows in or out of the battery. (Which is why excessive use of the EV switch is inefficient.) I have read of Toyota techs who will install the EV switch for you, but it is an unauthorized mod, and most dealerships won't. You can install it yourself or get a friend to do it. It's a relatively easy install, and there are several implementations. The cheapest being Evan's DIY version in the Knowledge Base, and the easiest being the $45 switch from Costal Tech. The warranty issue generates much heat and controversy. There are LONG threads arguing the point. Often quoted is a statement from Toyota that adding EV capability AND converting the car to be a plug-in hybrid will void the warranty. Toyota has never pronounced on the EV switch alone, which is standard in the Japanese and European versions of the Prius. All Priuses have the same software. The aftermarket switches access exactly the same software as the standard switch does. One important use for the EV switch is to prevent the engine from starting when you are just going to move the car a short distance.
Hmmm... We can quibble here. What you're referring to is the planetary gear set, which has a fixed ratio and divides the ICE torque between MG1 (the "generator") and MG2 ("motor" attached to the wheels). Just because the gears are fixed, it does not imply that the electrics are being used in the sense of providing a large proportion of the motive power. MG1 can be controlled to spin while the ICE is running, or stay stationary, or even spin backwards. In doing so, it can present a load to the ICE that changes over a very wide range. Whatever load is NOT used by MG1 is "diverted" to the wheels. It is possible for the ICE to drive the wheels with MG1 not spinning at all. But I will grant you that in the vast majority of driving, MG1 will spin and it's output will be used by MG2 to add motive power to the car, in many cases without need of the battery. But even in this case, there is energy lost in generating the power by MG1 and sending it to the wheels by MG2. ALL of the energy to drive the car comes from the ICE, at one time or another. Remember: Prius is NOT an EV! (just ask darell)
It has not been mentioned, but the vehicle starts and runs the ICE when you turn it on from a cold start not only to warm itself and the cats up but also to do a vehicle functionality test. You will see this on the MFD energy display if you are not moving just after startup. The ICE directly charges the battery for a moment and then stops charging, but continues to run (to warm itself and cats up).
The only thing like that, and this was for gas only cars, was an aftermarket chip (sold at speed shops) that took the place of the one that came with the car. I even saw ads for a selector box so you could switch it depending on the need (including one for the original chip when you took it in to be smogged). Doubt if that will be done for the Prius.
