Prius won't start...ready sign never turns on

I had this problem yesterday!! I was so freaked out!
I lubed my brake caliper sliding pins. Before starting, I disconnected the 12V battery. After reconnecting, the car wouldn't go into ready mode! I was terrified!

Solution: Disconnect 12V battery and re-connect. Phew!

 

I have a 2011 Japanese Prius.I encountered this problem last night when my car wasn't not responding to the remote, so i opened the car with the key to get in. as i tried to start the car by holding the brake and pressing the start button, there was no indication on the start button or the screen, i tried the same for 30 seconds and after a few attempts it started. after the startup all the settings were reset including the stereo, climate control and the trip meters including their past histories. Can anybody help me in identifying what the issue might have been? Thanks

 

Check the 12 volt battery.

 

Thanks, ill get it checked tomorrow

 

I recently bought a 2010 with 85k miles on it. I didn't have a chance to use it much yet, as I was busy upgrading the factory radio and installing a backup camera. I have been disconnecting and reconnecting the battery's negative cable while wiring and installing the new stereo.
A couple nights ago I started having the same symptoms (car would not go into Ready Mode). I checked the battery voltage with a multimeter and it was reading 9V, way too low. I connected my battery charger/tender overnight. Checked again the following morning, and it was only at 10v. I got a Bosch replacement battery from PepBoys and I left it charging overnight (who knows how long was the battery sitting on the shelf). I'll report back see if the issue is gone with the new battery (hopefully tomorrow).

 

Just a quick update. New Bosch battery finally finished charging. Reinstallation was pretty easy, perfect fit. Checked voltage on the battery and it was reading around 12.3v. Started the car without any issues.
Since I'll be probably doing mostly short drives, I'm going to install a battery harness, like the ones for motorcycle batteries, to tender/maintain the battery on my Prius once a month.

 

That's strange. A brand new battery, freshly charged, I'd expect immediately after charge it'd be around 13.0 volt (due to surface charge), and around 12.7 after a day or two, with some driving. Typo??

 

I measured it right after I finished re-connecting it to the vehicle. May explain the slight voltage drop? It seems normal to me, considering the vehicle was not running when measured, just quickly measured it off the battery posts, who knows. I'll test again tomorrow, before and after IGN-ON and report back.

 

it happens as some unscrupulous auto stores. once it tried to replace a totally discharged battery that came in an used car with a brand new from advance auto (i had a 30+% discount coupon they used to have). they didn't have one in stock and it took 2 days to get it. i got suspicious as it came with 1 year old sticker but i had no choice as there was not another one available (rare car). the voltage tested OKish, but the battery failed load test at home. the dead one, 3 year old one performed better on load test (after charged of course). I'm thinking the "new" one sat totally discharged for a year (or longer). i'm still using the old one 2 years later. this is in my son's saturn car (battery in trunk, just like prius!).

 

That's exactly why I charged it before installing it in the car. I saw the sticker stating the battery was manufactured a year ago. I got it at a Pepboys close to where I work, and usually they are pretty good at exchanging items if there's problems with it.

To update on my previous post, I checked the battery readings this morning.
Battery voltage, car turned off: 12.65v
Battery voltage, car turned on (ign-on): 14.35v

 

Last time I was buying a battery in Canadian Tire, they had a nice digital load tester, tested the battery before I paid, demonstrating good voltage, and CCA well above the sticker. I'd brought along my Solar BA5 cheapie tester, but they offered.

 

12.65 is better, still a little iffy for brand new and freshly charged. Hmm. Ask them to test CCA (Cold Cranking Amps)? Or CA (Cranking Amps), if that's displayed on the sticker. Either will do. A store selling batteries should have a decent digital load tester, if they don't do not know.

 

That's a good idea. I'll try to stop by PepBoys or AutoZone and see if they can test that for me.

 

Hey guys I am having this issue on my 2013 Prius, checked the battery and I am getting over 12 volts, key fob battery is still good, brake lights work. The car will start with the emergency start sequence and drives perfectly, but when I try and start it normally the ready light does not come on and the car says depress brake pedal. I have the TIS software and it gave me a B2284 error so I replied the Stoplight Switch and the problem is not resolved. What are the other parts that could be involved, can it really be a bad power control computer, my car only has 80000 miles? My old Prius has over 260000 miles and still runs like a champ.

 

I think I my have narrowed it down to the Stop Light Control Relay, when I press my foot on the brake pedal there is an audible clicking noise coming from the front passenger side near the glove box. As I was testing I pressed on the brake and all of a sudden I didn't hear the noise and the green start light came on, let go of the brake to test again and the clicking came back and the green light went off.

 

Sounds like you've figured out your problem... great work. But... there are points under the hood in the fuse box where you should check voltage. Don't just check the battery itself.

 

Where are these points? I would like to check these first before moving forward. Thanks

 

Sure, the +12V is in the rear of the fuse box, under a red cover which you flip open. The ground is... well... I know there's a big beefy ground on the inverter, which is close enough.

 

ELECTRICAL SYSTEM: SOFTWARERecall for 2010 Toyota PriusRecall AnnouncedFEBRUARY 12 2014NHTSA ReferenceNumber Affected
Summary: Toyota is recalling certain model year 2010 through 2014 Prius vehicles. In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. If this occurs, various warning lamps will be illuminated on the instrument panel and the vehicle will have reduced power allowing it to only drive a short distance.
Consequence: The vehicle may enter a fail-safe/limp-home mode that limits the drivability of the vehicle. The hybrid system could also shut down completely resulting in a vehicle stall, increasing the risk of a crash.
Fix: Toyota will notify owners and dealers will update the software for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU, free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will replace the inverter assembly with a new one at no charge. The recall began on March 21, 2014. Owners may
For detailed information & supporting documents, see the official NHTSA page concerning recall #14V053000 »
HYBRID PROPULSION SYSTEM: INVERTERRecall for 2010 Toyota PriusRecall AnnouncedFEBRUARY 12 2014NHTSA ReferenceNumber Affected
Summary: Toyota is recalling certain model year 2010 through 2014 Prius vehicles. In the affected vehicles, the Intelligent Power Module (IPM) inside the inverter module (a component of the hybrid system) contains transistors that may become damaged from high operating temperatures. If this occurs, various warning lamps will be illuminated on the instrument panel and the vehicle will have reduced power allowing it to only drive a short distance.
Consequence: The vehicle may enter a fail-safe/limp-home mode that limits the drivability of the vehicle. The hybrid system could also shut down completely resulting in a vehicle stall, increasing the risk of a crash.
Fix: Toyota will notify owners and dealers will update the software for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU, free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will replace the inverter assembly with a new one at no charge. The recall began on March 21, 2014. Owners may contact Toyota at
For detailed information & supporting documents, see the official NHTSA page concerning recall #14V053000 »

 

Makes no sense to me that it would be the battery. I don't see how trying it over and over it would start if it were the battery. I would think with multiple tries it would be LESS likely to start