Alarm Problem

[paultnl]

I have just been told at work that the alarm on my 06 Prius T Spirit has been going off several times a day for the last few weeks for no good reason. I have not had any problems with it parked overnight on the drive so wondered if anyone had any suggestions on what to check.

[FROSTYBALLS]

If the alarm isn't going off at home, I would suggest it is a characteristic of where it is parked at work.

Is it parked in an open area or on the road - could it be caused by wind, passing vehicles, etc?

[Chris Dance]

Ensure no sun glasses are stored in the top storage box near the top of the front windscreen.

I had a similar situation when I was parked up in an Essex Village. A new radio mast had been installed in the village and it played havoc with car alarm systems. I think they cured the problem by lowering the signal.

Heavy Traffic passing sometimes set off the alarm system on a Volvo I owned. I had the sensitivity of the alarm adjusted which cured the problem. If your Prius alarm has not been tampered with I doubt it is a traffic issue.

Have any of your work colleagues had the problem with any of their vehicles?

[Grumpy Cabbie]

Weak 12v? How old is the 12v Battery? Is it original? Alarm issues are often a sign of it failing. There are detailed instructions in the forum on how to check your 12v. Don't trust the car or the dealers apparently.

Otherwise is there a fly or moth stuck inside setting off the sensors?

Thirdly, has 4g been installed in your area of late or are you near(ish) a phone mast? There is a post in here about problems on my street with three Toyota owners all having alarm and locking issues due to an O2 4g mast being switched on. O2 use the lower frequency 800 mhz band. It was reported to O2 who sent someone the next day to their mast, who spent most of the day there and when the mast was switched back on the problem was resolved, though O2 denied it was them!?! :)

[paultnl]

Thanks for the feedback guys, keep them comming.

As it is a "green" car, I get to park in a premium spot next to the office with no passing traffic or other obvious reasons to trigger the alarm.

I will check for local cell towers but I do not think they will be the issue.

Can anyone tell me where the sensors are so that I can check for insects etc.

As far as I know it is still on the original 12V Battery but has not shown any of the other signs of failing (slow locking etc.) but I have been thinking of replacing it due to the age.

Is there a way to turn off the alarm as it is bothering some collegues near the parking bays?

Thanks for all your help.

Paul

[MEP's Yaris GS]

If like the gen 3 it'll have a switch near the interior light to deactivate the alarm (or at least some of it) but I think this has to be hit every time you want it to only part/not set and not a hit once and forget button.

Not sure where your internal sensors are, I can't say I've seen any at all on my Gen 3 PiP even though its also got an alarm (tried it out by opening the door when not deadlocked).

[FROSTYBALLS]

Usually any interior switches de-activate the internal sensors for when one has an errant pet or mother-in-law in the locked car.

[Grumpy Cabbie]

As far as I know it is still on the original 12V battery but has not shown any of the other signs of failing (slow locking etc.) but I have been thinking of replacing it due to the age.

They're about £95 fitted by Toyota. Could be prudent to sort it before winter.

What signs were you thinking a failing 12v on a hybrid would show? A traditional car would turn over slower and slower. With a hybrid it will either boot up the computers or not. Do a google for 12v failings and you'll find hundreds of posts similar to yours. The common indications are alarm issues and some locking issues but not slow locking as such.

Best way to check the 12v is a multimeter when the car has been left overnight and NOT in Ready mode. If it is less than 12v then get rid asap. Another way to check is to get in the car in ACC mode (not in Ready) and then wind all windows down and back up again in one go. If they're slow or the interior lights go dull or off then the 12v is probably dud - esp from 2006. Try the windows again in Ready mode and if they whizz up and down then you know the problem.

But the 12v is the Toyota hybrids achilles heel. Even the Toyota dealers don't really get it. If it does fail be VERY careful when jump starting the car. Do not have the doner car running. The Prius 12v is almost a large motorcycle Battery.

http://www.toyota.co.uk/service-and-maintenance/repairs-and-parts

That link will give you details of the fixed price replacement.

[PeteB]

In the meantime, if using the internal button to kill the ultrasonic sensors each time you switch the car off doesn't stop the problem, you can avoid using the alarm altogether by locking with the emergency key. However, you won't have double locking (deadlocking) if you do this.

[paultnl]

Just checked the Battery, it was down to 11.2v so I will get a new one tomorrow. Has anyone done a DIY change or is it best to leave it to the dealer?

[Grumpy Cabbie]

Just checked the battery, it was down to 11.2v so I will get a new one tomorrow. Has anyone done a DIY change or is it best to leave it to the dealer?

It's £95 fully fitted.

Aftermarket versions can be had for about £50 but need tinkering on the vent. The vent is important as the 12v is in the cabin and you don't want to be breathing the fumes, however unlikely. Apparently the non standard tube is either too big or too small and needs some persuading.

It depends how much hassle you want in life. Some are happy to tinker for the £40 saving, others aren't.

[paultnl]

Only £95, I think I will leave it with the dealer.

Thanks for everyone's help

[Grumpy Cabbie]

Well report back and let us know if it was all fixed.

The Prius can take a while to charge a 12v so make sure the one they're giving you is nicely charged. Maybe take it off the car and charge it yourself when you get home or give the car a good long run of a few hours; yes, hours.

But hopefully the problems will resolve with a new 12v and you will probably find mpg's will start to creep up a little too.

[MEP's Yaris GS]

Does anyone know if the PiP charges the 12v at the same time as the HV Battery when plugged in and charging to always keep it in top tip condition ?

[Grumpy Cabbie]

Does anyone know if the PiP charges the 12v at the same time as the HV battery when plugged in and charging to always keep it in top tip condition ?

Interesting question. I having a feeling it doesn't but you never know. The Leaf has a small solar panel as an option to keep its 12v topped up nicely. I wonder if such an option would be useful on a Toyota hybrid considering how small the 12v is in these vehicles. A small solar panel can't cost much as a part and could be incorporated into the hatch or even the boot spoiler.

[barrycoll]

I dont think that the solar panel in the roof of my Gen 3 is much good for anything other than lightweight fans...but perhaps it could trickle down to the 12v???

[Grumpy Cabbie]

Oh I forgot about that option. It was way too heavy and didn't really achieve much. Rumour has it that it was originally to power the a/c to some small degree, hence the size of the panel, but it didn't work that well so it just powers the fan instead. The solar panel on the Nissan Leaf is about 12 inches by 6 and adequate to trickle the 12v. Something similar on a HSD car could be handy.

[RunningInPleasePass]

Does anyone know if the PiP charges the 12v at the same time as the HV battery when plugged in and charging to always keep it in top tip condition ?

Found this :

http://www.toyotaownersclub.com/forums/topic/151779-12v-battery-charging-in-a-pip/

[IanIanIanIan]

I had alarm troubles. It was a small fly in the cabin disturbing the movement detector.

I have also heard that quickly changing sunshine and shadows may cause a problem, I assume there are air convection currents produced that may also trigger the detector.

[Grumpy Cabbie]

I had alarm troubles. It was a small fly in the cabin disturbing the movement detector.

I have also heard that quickly changing sunshine and shadows may cause a problem, I assume there are air convection currents produced that may also trigger the detector.

It was suggested, but an 8 year old 12v, which normally have a useful life of 5 years, was reading less than 11.5v. Anything less than 12v is poor on a Prius.

The 12v fails quietly in a Prius and it can cause all sorts of weird and wonderful electric gremlin issues; unlocking issues, alarm problems, weird warning lights and error codes, falling mpg's. You get the picture.

[paultnl]

Update,

Had the new Battery fitted on Saturday and apart from the alarm triggering when I parked 5 mins after I picked it up from the garage (it hadn't had chance to charge) I have had no further problems.

Thanks for all the comments and help.

[Grumpy Cabbie]

The Prius charges a 12v much slower than a car with an alternator. Give the car a good couple hour run if you can. Even if you just take the Mrs shopping and sit in the car with it in Ready mode. It'll charge when in Ready, even if the engine isn't running.

But glad you got it sorted. Even if it didn't, at least you now how the 'insurance' of having a new 12v with winter coming.

[ph47mf]

My alarm goes off every time I park it in a nearby Powerleague 5-a-side football place car park. It doesn't happen anywhere else but there. No one inc the dealership people can solve this mystery. I've settled with locking the car with the key like the 80s.

[Grumpy Cabbie]

Any phone masts, police stations or taxi offices near by by any chance?

[ph47mf]

i dont know, it could be anything, it's quite a built up area.