New Prius peculiar start-up problem

Re: New Prius peculia start-up problem

try disconnecting the 12v battery for 5 min. and then reconnecting to reboot the computers.

 

Re: New Prius peculia start-up problem

Don't know what to say what's causing your starting difficulty but here's a couple of questions; You do realize the ICE doesn't start immediately after pushing to the start button? I'm usually all the way out of the garage before mine starts up. Also are you sure you're pressing the brake firmly before pushing the start button? When you park the car for the night, you press the Start button to shut it off, not just the Park button? I hope you solve your problem soon because it would be a real PIA for me if it were my car.

 

Re: New Prius peculia start-up problem

While you're pressing the brake, are your stop lights on? If your brake light switch above the pedal is loose or mis-adjusted you could be having a problem with it recognizing the brake is depressed. The touch lights being on without pressing them makes no sense.

 

Re: New Prius peculia start-up problem

Sounds like it wants to start up but then shuts down. I'm going way out on a limb here, but what's the chances the FOB transmitter is sending a false RF causing this problem? Try the "other" FOB and see if the problem changes.

Also, Jim's suggestion about a faulty brake switch is a possibility that your dealer should investigate.

Happy Motoring,

Tom

 

Re: New Prius peculia start-up problem

Once you get the "ready" light, you can press the accelerator to the floor and the ICE (gas engine) will start up without delay.

I'm thinking the NAV might not be related and might be a cold temp/boot up issue.

Silver City is nice. I base camped out of there on a motorcycle trip two summers ago before working my way up to Colorado.

 

Re: New Prius peculia start-up problem

Yes, true. My question assumed the OP might have been waiting to hear the ICE fire up while sitting still.

 

Re: New Prius peculia start-up problem

I occasionally experience the same thing and I think it is 12 volt battery related.

One "voodoo" item that seems to help is to let the brakes pressurize prior to hitting the "Start" button. I don't know if this actually helps, hence why I call it "voodoo".
The 12 Volt battery boots up the computer (and when successful, puts the car in "READY" mode). You'll note in your pix that the READY mode isn't lit on the first screen shot after pressing the Start button. In my case, it is not the brakes, because when it last happened at my house, it was dark and I could see my brake lights reflecting off of my wife's van, so I know that wasn't the cause.

The reason for waiting is that I'm not sure if the brake pressurizing is putting a load on the 12 volt battery, but I do think it is. You'll notice when you first open the door, you'll hear a "whirring" noise that carries on for about 10 - 15 seconds. This is the sound of the brakes pressurizing (so I've read here).

One time when I booted up the car, I also turned on the windshield wipers. They moved REALLY slow (like nearly dead battery on a normal car type of slow). Once the car went into ready mode, they sped back up to normal speed. You'll also notice when you first boot up, that the icons will be a bit dull in brightness. Once the car hits Ready mode, they brighten up. Thus, I try to limit the loads I put the car under when I start it up. (Lights off, wipers off, etc).

You'll probably also find that your Nav system may reset during periods of low battery. You can check your battery charge by running a set of commands on the Nav Screen. One way was to turn the headlights on and off 3x. However, when I did that, my NAV screen would reset, and I'd have to do it over and over again. Finally, someone posted up how to do the "finger dance" as a way to get the battery charge screen loaded.

You might want to get a voltmeter and measure on the battery terminal (mild pain in the butt). You can compare the voltage on days it does start with days it doesn't start. My battery isn't holding a full charge (it will go up to 12.1 - 12.4 V when I'm done driving for an hour, but will drop to 9.4 volts when parked overnight). On days it won't start, it will drop to 9.2 volts.

I'm strongly considering having the battery replaced (expensive) or having a yellow top battery installed for me (even more expensive). I'd take it to the dealer and complain, but they will charge me $125 to check it, and they may determine that the battery is "marginal" (Marginal = 10 volts). My 9.4 volts = 9 volts (with rounding), but if they get it and it reads 9.5 volts, that will round to 10 volts and will be marginal (and I'm out $125 and still have a weak battery).

This is likely a more common than reported problem with the Prius. There is speculation that Toyota got a bad batch of batteries. Mine has never been drained to explain its poor performance.

 

Re: New Prius peculia start-up problem

While you were back theree with the battery did you take a voltage reading? If you hook up a trickle charger how long does it take to show that the battery is fully charged? Is the clock keeping time?

 

Re: New Prius peculia start-up problem

since you recently purchased it and it is a 2010 model it could be that the car sat on the lot for a while in those chilly temps and with whatever it is the also seems to be draining the 12V batts (new here, but seems common!) affected yours before you finally gave it a "forever home" in dog-adoption speak...? would Optima batteries help the Prius maintain the 12V battery life? i could be completely off base in all this

 

Re: New Prius peculia start-up problem

This is definitely a weak 12v battery. When most types of batteries are cold, especially the lead-acid type used in the Prius 12v system, the output is greatly reduced. This means that a marginal battery may be too low to get the car to boot properly. The 12v battery does not "start" the engine, it only boots the computers and closes the main relays on the traction battery. Once this occurs, then a DC to DC converter takes power from the traction battery and supplies the 12v system which also allows the 12v battery to recharge.

What's happening is when you put a load on the battery initially it sags too low to boot the systems properly, but after a bit the current flowing in the battery heats the electrolyte up enough to generate a bit more power and the car then boots properly.

This problem is exacerbated because most 12v charging systems, including the Prius DC/DC converter, are not temperature compensated. This has the effect of never really allowing the 12v battery to fully charge when it's cold. A temperature compensated charger will increase the voltage when the battery is cold to allow a complete charge.

It's possible the battery simply got weak, and you haven't had the car in ready long enough for it to get a reasonable charge. If you have a battery charger, I would charge it overnight and see if the problem is solved.

Otherwise I would suggest you demand the dealer replace the battery under warranty, as you have proven that at the very least it's low enough to be unable to properly boot the car.

If your car was out of warranty, I would recommend you replace it with a superior battery, such as the Optima.

 

Re: New Prius peculia start-up problem

A small charger placed on the battery overnight will likely solve the problem. But if the problem continues, you should consider replacing the 12v battery.

 

Re: New Prius peculia start-up problem

This is the weakest link in the system, the 12v aux battery. Having two Prius, I highly recomend the optima upgrade.

Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10

This kit comes with everything you need.

 

Re: New Prius peculia start-up problem

I don't have the manual in front of me, but is the dealer supposed to check the battery when you bring it in for service?

 

Re: New Prius peculia start-up problem

I second Dave's recommendation. It will solve the problem for a long long time!

 

Re: New Prius peculia start-up problem

Most service departments have a Midtronics tester that will create high-frequency high-current pulses to accurately assess the real condition. This test even works on a low battery that is otherwise healthy and will indicate this condition. If the battery is marginal though, especially if it's tested when warm, it may just pass and then still leave you stuck on a cold day.