Ready Light - Not Ready!

[OvertheHill]

Has anyone else had the following issue. Every so often when I press the start button everything lights up except the Ready light. I then have to switch off and start again, and it usually comes on the second time but very, very occasionally the third or fourth.

[Sagitar]

Check your 12v Battery for charge level.

[OvertheHill]

Is it a symptom of a low Battery?

[Hybrid Harbour]

Sounds more like you have not got your foot on the brake hard enough, and it thinks you just want the radio on...

[timberwolf]

In no particular order and some have already been mentioned.

1a) Not pressing the brake pedal when pressing start

1b) Mat under brake pedal!?

2) Low 12V Battery

3) Faulty or incorrectly adjusted brake pedal switch

4) Faulty gear shifter

5) Faulty ECU or fault in wiring or connector.

[Grumpy Cabbie]

I'd be curious to know what age and/or mileage your car is.

Timberwolf has quoted the main issues causing this symptom you're experiencing. Aapparantly there are issues with the brake pedal switch going out of adjustment (or even faulty). There are a number of 'levels' to this switch, so your brake lights might come on BUT it might not be registering to allow the car to go into Ready.

[OvertheHill]

Hi - my car is a September 2009 with only around 22,000 miles on it. I've definitely got my foot on the brake all the way down so maybe I'll ask at the dealers next time to check the switch

[Grumpy Cabbie]

In that case I'd be tempted to turn off your boot light and/or make sure the hatch is fully shut and not running your 12volt low. It's a long shot but your 12v shouldn't have died yet unless you've run it flat by leaving your sidelights on etc. It could also be a dodgy brake pedal switch. Have you checked your 12v with the old "run all your windows down and up" when not in Ready after the car has stood overnight?

But as your still under warranty I'd get your dealers to give the car a once over and see if there are any spurious error codes etc.

[timberwolf]

Hi - my car is a September 2009 with only around 22,000 miles on it. I've definitely got my foot on the brake all the way down so maybe I'll ask at the dealers next time to check the switch

I was wondering what was meant by "all the way down"?

I think I only press my brake pedal down part of the way down when starting the car.

[OvertheHill]

I guess I mean as far as I can push it! I haven't left anything on but I do leave the car for 4 or 5 days at a time but as I say it is intermittent. Will get the dealer to check

[OvertheHill]

Okay - update. I was sat listening to the radio after a 40 minute drive. Normally the car displays a message saying it is turning the radio off to conserve the 12v Battery. Instead it went dead, the screen started flashing on and off and the triangular yellow warning exclamation flashed. Pressing the start button did nothing. There was barely enough juice to lock the central locking. I came back after a few hours and it had recovered and started up.

Took it to the dealers who diagnosed a failed 12v Battery which is apparently so rare the replacement had to come from Japan. All fixed and everything is back to normal. Thanks all, especially those who suggested it was the Battery.

Cheers

[timberwolf]

Is this a regular thing that you do listening to the radio with the car in ACC mode?

[ph47mf]

now you know where your problem is

[Grumpy Cabbie]

Yep sounds like we've found the problem. Why listen to the radio using the 12v in Acc mode when you can listen to the radio, have the a/c on and be in comfort in Ready mode using the massive HV Battery whilst still not using any petrol?

Personally I'd be interested in whether this is a warranty claim as it is down to user error that caused the failure. If anything, my 12v should have failed first, what with all the extra CB radio, meters, computers attached to it for 10 hours a day. I could often sit for an hour between jobs with all this equipment running.

Mine's a 2009 with 65k miles. No longer running it as a taxi now though.

[AGL]

Yep sounds like we've found the problem. Why listen to the radio using the 12v in Acc mode when you can listen to the radio, have the a/c on and be in comfort in Ready mode using the massive HV battery whilst still not using any petrol?

Personally I'd be interested in whether this is a warranty claim as it is down to user error that caused the failure. If anything, my 12v should have failed first, what with all the extra CB radio, meters, computers attached to it for 10 hours a day. I could often sit for an hour between jobs with all this equipment running.

Mine's a 2009 with 65k miles. No longer running it as a taxi now though.

Are we to just call you Grumpy from now on, then?

[Grumpy Cabbie]

Yes :)

[OvertheHill]

I'm not sure why listening to the radio for a short while very infrequently counts as user error, and it certainly shouldn't damage the Battery

[kithmo]

I'm not sure why listening to the radio for a short while very infrequently counts as user error, and it certainly shouldn't damage the battery

Absolutely true, but you have to remember that the standard Prius Battery is not a heavy duty cranking Battery like on a normal car and won't stand up to the same amount of use.

[Grumpy Cabbie]

User error in that will have inadvertantly run the 12v Battery too low too often.

To be fair, the 12v in the Prius is weak as it only needs to boot a computer to start the car rather than crank the engine in the traditional way. To also doesn't like deep discharge cycles as it is assumed that people will leave the car in Ready whilst listening to the radio etc.

It not a personal dig, but equally it's not a fault with the car that you ran the 12v Battery right down and damaged it. Trouble is, once a 12v is knackered, it'll never be the same again. In future, if listening to the radio whilst waiting for the Mrs to go to the Dentists or shopping, you're better leaving the car in Ready and it will power items from the big 1.2 kwh HV Battery as well as continue to trickle charge the 12v. It is unlikely any petrol will be used in that hour.

To be honest, the HV battery in the car is almost powerful enough to run your house for a little while and longer if using the engine to top up. It has a 1.2 kwh rating.

[tarler]

I know I am a late comer on this conversation but I disagree that it is a user issue. In fact I don't get the whole 12v Battery vs the main electric power. If the 12V only option is there to do what it would do on a normal car then that 12V Battery should be able to do the same. On a personal level, that whole partial on/full on thing is really a pain. You know how annoying it is to press the power button and think the car is on but it isn't. I didn't buy a Prius (at first) because I thought the A/C didn't work or was terrible because of it. I hit the button and power lights came up, radio on, climate control on. But that dang air never got cold. I didn't know that there were different levels of being on. Even now that I know, I have problems/issues with it. Sometimes I hit the power button (with my foot on the brake) and think I turned the car on but it isn't. It is so frequent that sometimes I think it didn't turn on completely (the 'P' didn't go solid and the speed digits didn't show up right away) that I hit the button again to only see it finish turning on completely and then turn off because I hit the button again.

[kithmo]

I think it's pretty much agreed that the 12v Battery should be more sustantial.

As far as the Power button goes, have you tried pressing it instead of hitting it LOL.

It does take a couple of seconds to boot up the system (which is pretty fast when you compare it to a desktop or laptop computer) and it gives you a beep when the "PRIUS" logo disappears and it is ready. If it's not "READY" in say 3 seconds then there may be a problem with it.

My routine is, foot on footbrake (and release foot operated parking brake if on) and wait until the brake pressure pump stops whirring, then power on, listen for the beep, then into "D" (or "R") and drive off.

[robbo40]

Not so rare as the dealer is saying. over the last three weeks have had the same problem. I have recharged the Battery by using the ready engine and just letting it sit in the drive, the Battery has recharged. Today same problem, car goes into service on Monday for second service with 13k on the clock. Will let you know if a Battery is diagnosed as problem. Have 5 yrs warranty on car

ps NOT A NEW MEMBER, but couldn't remember my password:)

[Grumpy Cabbie]

Once a 12v Battery has been run too flat it's never, ever going to be the same and will fail sooner than later.

You should argue a new 12v under warranty and I'm sure if it's your first warranty claim, they'll more than likely be accomodating. However (and it's a big however), you're way way overdue a service. Although they allow a little leeway a whole 3,000 miles might be pushing it. Maybe PartsKing might confirm.

Good luck and hope you get it sorted and trust you'll keep us all updated.

[robbo40]

Hi Grumpy, don't seem the same without the following cabbie:)

This was my SECOND service first at 12 months...not much mileage these days!

Car was taken to service today and after diagnostic checks nothing recorded in the ecu and Battery is charging at 14.2

I have raised the issue about replacement Battery but they feel it does not need changing at this time because of the high charge rate, although they have accepted if it is required they will change under warranty. Had no problems recently and it starts all ok with no funny signals from the dash panel. Incidentally on the service sheet it records oil changed and Mobil o.2 used. Queried it and mechanic said its the norm now?

[Sagitar]

I know I am a late comer on this conversation but I disagree that it is a user issue. In fact I don't get the whole 12v battery vs the main electric power. If the 12V only option is there to do what it would do on a normal car then that 12V battery should be able to do the same.

But it isn't there to do what it does in a normal car. As has already been said, its main purpose is just to boot the system, after which the traction Battery provides all the necessary electrical power. A normal car has a high capacity 12v Battery because of the starting duty it has to perform. If you want the same capacity just to run auxiliaries, there is a considerable weight penalty and it would be a bit silly considering that you already have a large traction Battery capable of providing more than you will ever need. If you know that you're going to make extensive use of auxiliary equipment with the car stationary, it is simple enough to leave it in the Ready state in the way that Grumpy describes.

The thing to look out for is inadvertent power use with the car switched off. The most common one seems to be failure to close the boot lid properly so that the interior light stays on. I did it to mine once and now I turn off the light at the manual switch and only put it on when I need it.