2008 Prius intermittently not starting

[2008 Prius Owner DH]

I have done a lot of research on this issue and see others have had similar/same issue and I don’t see resolution.

My 2008 Prius was totally dead about a month ago for no apparent reason after I had just driven it 2 hours before. I had it jumped and all was well. 3 weeks later I let the car sit a week while out of town and car was dead again, no lights no clicking of alarm just completely dead. I had it jumped again, drove it 30 min and when I turned it off it was dead again. THEN the car came back to life on its own in the driveway, engine in and alarm blaring. Got it to a shop next day and it died at shop. They said it was an alarm issue. Took it to dealer. They said it was alarm issue. Had alarm removed and drove it for an hour, started fine, the  45 min later dead again! Had it jumped again. Took it to new repair shop and they said it’s my hybrid Battery. I did my own research and realized that thy hybrid Battery does not start the car. So I get it back to dealer, alarm removed and ask them to diagnose. 2 days later they say car is starting fine, no issues found. So  I pick up my car, they drive it to me, I turn it off, it’s dead again! This time I see door ajar light on and can hear door lock and unlock with remote so it has some power. They did an immediate Battery test. Battery tested fine and healthy. Car is still at dealer and they seem stumped as I am and really don’t want to scrap a Toyota with 137,000 miles that’s been so reliable and I’ve maintained it very well. I have 2 young kids and can’t afford to keep getting stranded!

Has anyone found the cause as I’ve seen other people have the same issues?

 

 

[Catlover]

Must be frustrating. I would be checking fuses, not that they will be blown, but for there contact. Disturb them, clean contacts by light cleaning, 

what do you do to jump start the car? It’s the 12v Battery that brings the cars HV Battery into life, and it doesn’t take much of a jump to give the 12v Battery enough to kick the HV battery into life. I use a device costing about £35 and is little bigger then a 6” mobile phone. It has jump leads with crocodile clips and is strong enough to jump start a car 3 or 4 times. Try Amazon or eBay.

[altocumulus]

I had a similar problem with a 2007 plate. The car refused to start on a couple of mornings. I don't think anyone really got to the bottom of what the issue was. I charged up the Battery on both occasions - though the Battery itself was healthy. Usual problem - take it to a garage and they maintain nothing amiss.

I purchased a hand-held powerbox from Amazon - amazing little thing. I didn't have any further problems with the 2007 plate! but it came in handy when my RAV4 Hybrid played up.....

(ps the powerbox I have doesn't have cables long enough to reach the two jump-start points under the bonnet! Why you can't jump at the Battery I don't understand; it's easy enough to get to it in the boot.)

[Catlover]

Geoff, you can use the jump at the Battery. I done it a few times. Suppose more convenient under the bonnet if the boot is full of luggage whatever.

[altocumulus]

Thanks Joe.

 

I wonder why Toyota suggest otherwise - even on the phv they have one connection to the Battery and the other to the other side of the engine (underneath a cover!)

[kithmo]

1 hour ago, altocumulus said:

Thanks Joe.

 

I wonder why Toyota suggest otherwise - even on the phv they have one connection to the battery and the other to the other side of the engine (underneath a cover!)

Safety I suspect. no chance of a spark near the Battery if you're jumping from another car when you take the leads off.

 

[2008 Prius Owner DH]

Thanks for folks that have weighed in. I have been getting it jumped under the hood each time and also bought a jump starter off of Amazon just in case. Very discouraging that this is happening. Very I tersting that RAV4 Hybrid has similar issues (?) as I was literally a few months away from buying one and now I am seriously reconsidering. Still hopeful that someone who reads this may have a suggestion as to what the actual problem is.

Thanks!

 

[kithmo]

I'm wondering if it's something to do with the key slot, poor or intermittent connection maybe ?

[ian rooke]

Hi have you checked  if any lights like the boot light are on it can flatten the 12v Battery in less than 5hours (very small battery) also how old is it if you get more than 5 years out of it you     are doing well. 

[2008 Prius Owner DH]

I had it at the dealer and will change dealers Monday because I have low confidence where it’s at. I had it at two other garages and they all say Battery checks out fine and no loose connections.  Now whether they actually checked key slot or fuses or lights I can’t say for sure although they say they have. I’m not so handy with cars so relying on the mechanics which has proven useless and costly. I am changing dealerships in hopes that new eyes can possible figure this out. It is weird how symptoms changed though from flat out dead to not starting with door ajar light on to trying a few times without success then putting key fob in as opposed to in console. Anyway still eager to hear others feedback if anyone has ideas since car will be sitting at dealer until they can look at it Thursday.

Thanks!

[QuantumFireball]

Sounds to me like the 12V Battery is bad, or something is intermittently draining the Battery e.g. bad door switches, etc.

When was the 12V last replaced? Have you measured the 12V load when the car is off?

[Sooty]

Have you changed the Battery in the key fob? A flat one can cause weired issues like yours/

[2008 Prius Owner DH]

Yes key fob Battery is new and Battery has been tested on, off, when car died at dealership and it always tests fine. I brought it to a new Toyota dealer yesterday so hoping when they do diagnostics Thurs they can find the issue.