Odd Startup Routine

[Sagitar]

In the last couple of days I have been experiencing an odd departure from the normal start-up routine.

I press firmly on the brake pedal and the Power switch light turns green as expected.

I press the Power switch and all the dashboard indicators light up except that the "Ready" indicator does not show. If I try to move the vehicle at this point, nothing happens.

If I press the Power switch a second time, the "Ready" indicator shows and all is well.

If I repeat the start up routine after only a short delay, then "Ready" comes up at the first push of the Power button as described in the manual, but if I leave the car for a significant period I again need to push the Power button twice in order to get the "Ready" indicator.

Am I doing something daft? Is it the first sign of a more serious problem?

I'm thinking of calling the dealer on Monday to ask for a check.

[Jan&tone]

Sounds odd to me too! Worth a call to the dealer, - just a thought though, you're not getting a bit 'blase' are you and pushing the power button too quickly after putting your foot on the brake?? We all tend to rush things when we get used to them...

[Grumpy Cabbie]

Push your foot harder on the brake!

There could be two faults here (both unlikely and more likely driver error ) either the brake pedel switch is faulty or the shifter is.

Easy way to check things is to try and engage drive or reverse WITHOUT pressing your foot on the brake whilst in Ready mode. If the car beeps at you, then you know the shifter is working OK. If that's the case, then it sounds like you are not fully pressing the brake whilst either entering Ready or whilst engaging Drive.

Let us know how you get on.

[timberwolf]

Other possibilities according to the owners manual including the disconnection of the 12V Battery or that READY may take longer to light in low ambient temperatures.

[Sagitar]

Sounds odd to me too! Worth a call to the dealer, - just a thought though, you're not getting a bit 'blase' are you and pushing the power button too quickly after putting your foot on the brake?? We all tend to rush things when we get used to them...

I don't think so. After it had happened a couple of times, I started to do everything in "very deliberate" mode.

[Jan&tone]

Sounds odd to me too! Worth a call to the dealer, - just a thought though, you're not getting a bit 'blase' are you and pushing the power button too quickly after putting your foot on the brake?? We all tend to rush things when we get used to them...

I don't think so. After it had happened a couple of times, I started to do everything in "very deliberate" mode.

I'd go talk to the dealer but before you do, make sure you can replicate the problem 'cos sods law says that when you are there it will NOT happen

[Sagitar]

Push your foot harder on the brake!

This was my first thought too. It makes no difference.

There could be two faults here (both unlikely and more likely driver error )

I also entertained the driver error option, but I cannot see what I am doing wrong - I even got out the manual just to be sure I was following it properly - and I have been starting the car successfully for 15 months now. It's not a complex or difficult routine, so what might I be doing wrong?

either the brake pedel switch is faulty or the shifter is.

I can't see how it would relate to the shifter and even a brake pedal fault is a bit difficult to see.

Pressing the brake pedal brings up the green light on the Power switch - if there was a fault there, I would not expect the light to come on.

When "Ready" does not show on the first press of the Power switch, it always does so on the second press and this does not involve any change in the status of the brake pedal. All of this takes place without any involvement of the shifter.

Your prompting has forced me to think it all through very carefully and I am beginning to think that it may be related to low voltage in the 12v Battery. I had a starting problem before Christmas related to low Battery voltage and I blamed myself for possibly not closing the boot lid properly and leaving on the boot light. Now I begin to wonder whether the Battery is "iffy".

I'll be having another look later this morning.

Thanks for your suggestions.

[ashpole]

Have you tried the other key fob? It might be your usual one is not talking back to the car when interrogated...

[Chris Dance]

I would recommend a visit to your dealer it does not take them long to check the 12v Battery or your key fob. Let us know the outcome please.

Regards Chris.

[Sagitar]

I am now convinced that it is a Battery problem.

I put a multi-meter across the Battery this morning and it read only just over 10 volts. I did drive the car for a few miles in daylight yesterday with no major electrical load so I would have expected to see 12 volts.

I then tried the starting routine and it displayed the problem I have described but it did start. I drove it a few miles and checked the no-load Battery voltage again and it showed 12.5 volts.

Re-starting the car to put it back into the garage went completely according to book.

I shall not be using the car for the rest of the day and I will check the battery again early tomorrow to see how it has held up.

[kithmo]

I am now convinced that it is a battery problem.

I put a multi-meter across the battery this morning and it read only just over 10 volts. I did drive the car for a few miles in daylight yesterday with no major electrical load so I would have expected to see 12 volts.

I then tried the starting routine and it displayed the problem I have described but it did start. I drove it a few miles and checked the no-load battery voltage again and it showed 12.5 volts.

Re-starting the car to put it back into the garage went completely according to book.

I shall not be using the car for the rest of the day and I will check the battery again early tomorrow to see how it has held up.

Did you know you can access the vehicle diagnostic screen on the T-spirit ?

You can do this in READY mode or in ACC mode.

Press the AUDIO button, select the HDD tab, press the DISPLAY button then tap the FM tab and then the screen just under it, repeat three times and the Diagnostics mode comes up.

On one of the menus it shows the 12v Battery voltage, mine showed 11.8v just now in ACC mode and dropped to 11.6v when I put it in READY mode and went to 14v with the engine running.

[timberwolf]

I am now convinced that it is a battery problem.

I put a multi-meter across the battery this morning and it read only just over 10 volts. I did drive the car for a few miles in daylight yesterday with no major electrical load so I would have expected to see 12 volts.

I then tried the starting routine and it displayed the problem I have described but it did start. I drove it a few miles and checked the no-load battery voltage again and it showed 12.5 volts.

Will a few miles really charge up the 12V Battery sufficiently?

[Grumpy Cabbie]

I am now convinced that it is a battery problem.

I put a multi-meter across the battery this morning and it read only just over 10 volts. I did drive the car for a few miles in daylight yesterday with no major electrical load so I would have expected to see 12 volts.

Have you had a flat 12v Battery issue with the car previously? 10v sounds way low and almost like one of the cells is dud.

From reading the US forums it can take the Prius about 8 hours to charge up a low 12v rather than 20 mins in a traditional car. If you've done lots of short journeys in cold weather and leaving lights on when not in Ready mode etc you might want to take the car on a long run or trickle charge the 12v. Just becareful not to overload it or fry the cars computers.

[Sagitar]

Did you know you can access the vehicle diagnostic screen on the T-spirit ?

You can do this in READY mode or in ACC mode.

Press the AUDIO button, select the HDD tab, press the DISPLAY button then tap the FM tab and then the screen just under it, repeat three times and the Diagnostics mode comes up.

On one of the menus it shows the 12v battery voltage, mine showed 11.8v just now in ACC mode and dropped to 11.6v when I put it in READY mode and went to 14v with the engine running.

No, I didn't know that.

I have tried to follow the routine that you have described but I cannot. I run into difficult at the point where you say "press the DISPLAY button then tap the FM tab and then the screen just under it"

Pressing the Display button changes the display in a way that partially masks the FM tab and if I tap the part of the FM tab that is still visible, nothing happens.

Perhaps I am misunderstanding your instructions?

[Sagitar]

Will a few miles really charge up the 12V battery sufficiently?

How do you define sufficiently? It clearly charged it sufficiently to bring the no-load voltage up to 12.5 volts.

I am used to testing the state of charge of a lead-acid Battery by measuring the specific gravity of the electrolyte, but that is not possible with the Prius Battery.

[timberwolf]

Will a few miles really charge up the 12V battery sufficiently?

How do you define sufficiently? It clearly charged it sufficiently to bring the no-load voltage up to 12.5 volts.

I am used to testing the state of charge of a lead-acid Battery by measuring the specific gravity of the electrolyte, but that is not possible with the Prius Battery.

I could be misinformed as it is info that I've picked up from various places...

My understanding from what I have read is that Prius has a weak design when it comes to charging the 12v Battery. Looking at my Gen 2 with the Scangauge 2, the 12V supply usually reads 13.8V, and that doesn't usually drop to 13.6V until I have been driving for at least a couple of hours - in my case I've concluded that a 7 mile trip to the shops is not really doing much charging of the 12V battery. If you want to charge the 12V battery after jump starting it, you are going to have to drive around for at least 4 hours - I could be wrong.

If your battery measured with no-load after resting for a few hours on the bench had a reading of 12.8 volts - from what I understand I'd call that fully charged. At 12.5V, I believe the battery is roughly 3/4 charged, assuming you didn't measure the voltage too soon after charging.

[Sagitar]

My understanding from what I have read is that Prius has a weak design when it comes to charging the 12v battery. Looking at my Gen 2 with the Scangauge 2, the 12V supply usually reads 13.8V, and that doesn't usually drop to 13.6V until I have been driving for at least a couple of hours - in my case I've concluded that a 7 mile trip to the shops is not really doing much charging of the 12V battery. If you want to charge the 12V battery after jump starting it, you are going to have to drive around for at least 4 hours - I could be wrong.

If your battery measured with no-load after resting for a few hours on the bench had a reading of 12.8 volts - from what I understand I'd call that fully charged. At 12.5V, I believe the battery is roughly 3/4 charged, assuming you didn't measure the voltage too soon after charging.

Thanks, that's very helpful.

I took the car to the dealer this morning, but they could find nothing wrong. According to them, the Battery is in good condition. It was showing 12.7 volts when they tested it, but of course I had just driven about six miles to get there.

Your comments make me think that the car is simply not being driven enough to keep the Battery charged. It is out most days, but only for short journeys. In the last week I didn't go anywhere that took more than about twenty minutes.

I think my next step will be to fit a trickle charger such as the Optimate, that I can just plug in whenever the car is in the garage.

[Sagitar]

I am now the proud-but-penurious owner of an Optimate4. It comes with a permanent connection for the Battery terminals that terminates in a plug to enable easy connection of the charger.

I put it on charge at about 2 p.m. this afternoon and nine hours or more later it is still charging.

I'm off to bed now and will check it again in the morning.

[Jan&tone]

I am now the proud-but-penurious owner of an Optimate4. It comes with a permanent connection for the battery terminals that terminates in a plug to enable easy connection of the charger.

I put it on charge at about 2 p.m. this afternoon and nine hours or more later it is still charging.

I'm off to bed now and will check it again in the morning.

Wow! A plug in Prius

[Sagitar]

Wow! A plug in Prius

I wish . . . .

The instructions and notes with the Optimate4 are not simple, but if I understand them aright (and I think I do)

the display that I am getting at the end of charging shows that there is a significant voltage reduction during the 30 minute test period that follows the achievement of full charge. This may be because the Battery is still attached to the vehicle and the vehicle systems are causing a discharge, but alternatively it may indicate a Battery fault.

So, I have disconnected the Battery from the vehicle and re-run the Optimate4 routines. Even with the battery disconnected, I still get the indication of a significant voltage reduction during the 30 minute test period. The Optimate4 notes are unequivocal at this point - they simply say that the battery should be scrapped and replaced.

This is however completely contradictory of the information given to me by the Toyota dealer a couple of days ago, who said that the battery was in good condition.

At this point I am flummoxed and can only think of taking the battery to an independent "expert".

[Jan&tone]

While you have the Battery out, which i guess is not easy, is it worth buying a new one anyway? I understand the Prius 12v is quite small??

[Grumpy Cabbie]

You might want to read the variety of 12v Battery related posts on the US Prius forum. Apparantly if you don't check the Battery out of the car you're wasting your time.

[Sagitar]

While you have the battery out, which i guess is not easy, is it worth buying a new one anyway? I understand the Prius 12v is quite small??

No, it's easy actually.

It's a small Battery, but I guess it will still cost an arm and a leg and I am not facing any emergency, so I can afford to develop my understanding of the situation before I jump.

[Sagitar]

You might want to read the variety of 12v battery related posts on the US Prius forum. Apparantly if you don't check the battery out of the car you're wasting your time.

Thanks Grumpie - I've read loads of stuff on Priuschat, but most of it is about earlier versions of the car. The arrangements around the 12v Battery on earlier versions are quite different than for the Gen3. The Gen3 12v Battery installation seems to have been greatly simplified. Getting the 12v Battery out of a Gen2 looks like a major engineering exercise.

Doing tests with the battery both connected and disconnected is an essential part of deciding whether the problem is with the battery or the car.

[Doesn'tExist]

I'm no electrician so I may be spouting pure nonsense. As you may have read our 4 month old Prius was rendered useless over the Christmas period, despite all sorts of theories on how I have left open a door, a light etc it turned out to be a faulty earth cable leading from the 12v Battery in the back which the dealer repaired. Upon pressing last Friday what really happened (well at least to the level still comprehendible to me) it seems to have been earth somewhere that was getting loose making the problem appear over a period of time and with the little to no journeys over christmas it just stopped.

As I said no idea whether that makes sense or not, but if you are looking might be worth a look.