Master Warning Light

[Blinkn09]

Hi all,

I've been browsing this forum for few months now without a post. I bought a 2004 Prius with about 8,000 miles about a month ago. Everything was fine and dandy until I got my windows tinted. I dropped it off at the shop and when it was time to pick it up, one of the guys reversed the car and I noticed the Master Warning Light appear as the car was backing up. I was terrified! So he turned off the car, got out and I jumped in hoping the light doesn't reappear but it does! I also noticed that it had a symbol on the monitor (car with an exclamation point). I looked it up in the manual and it was the hybrid energy system if I recall correctly. I didn't know but I drove it home =X. It drove normally on the way back. So when I got home I turned the car off, then on again to see what would happen and to my suprise, the light was gone!

I was still worried though. I went home and looked up recalls on the 2004 model and it said to do the ECU re-programming and to change out the steering shaft. So I took the car to the toyota dealership the next day and asked for the recalls to be performed...

They gave me a call a few hours later and said that I needed a new battery because they're claiming that they can't reprogram unless they have at least 12volts in the auxulliary battery (they said I only had 10 volts). I know that the auxillary battery is in the back and they didn't move any of the things that I had stored back there to check it. The headlights, dome lights and everything is strongly lit so it should suggest a strong battery. I'll check it using a volt meter later...

So here is my question: Do you really need a full 12 volts to reprogram? if so, is it easy to change out myself without any problems?

They're wanting to charge me $230 for the battery and labor. The reprogramming and the steering fix is covered underwarranty.

Any help or advice would be appreciated!!!!!!!



Thanks!!

[qbee42]

This problem has happened to others. The guys at the tint shop left doors open for a long period, which means the interior lights drained the small 12V battery. Given the age of your Prius, the battery was probably close to being dead, and this finished it.

You need a new battery. You can do it yourself, or pay the shop. The Prius takes a funny size, so if you do it yourself, take a look at the postings about that on this site.

Tom

[KK6PD]

"Well other than that, Mrs. Lincoln, how did you like the Play?"

You will have to drop a note of thanks to the tint shop, of course the battery was already on its last legs.
Consider it a "Mercy Draining."

How did the tint come out. Did you do the front windows, and if so to what level?

As far as the battery, you should be able to find one MUCH cheaper than that, and drop it in yourself.

Good Luck

[Patrick Wong]

Originally Posted by Blinkn09

... I bought a 2004 Prius with about 8,000 miles about a month ago...

They gave me a call a few hours later and said that I needed a new battery because they're claiming that they can't reprogram unless they have at least 12volts in the auxulliary battery (they said I only had 10 volts). I know that the auxillary battery is in the back and they didn't move any of the things that I had stored back there to check it. The headlights, dome lights and everything is strongly lit so it should suggest a strong battery. I'll check it using a volt meter later...

So here is my question: Do you really need a full 12 volts to reprogram? if so, is it easy to change out myself without any problems?

Yes, the service instructions relative to engine and hybrid vehicle ECU reprogramming require a fully-charged 12V battery to start the process. If the battery voltage were to sag during the reprogramming that might ruin the ECU beyond repair.

It is not necessary to physically expose the battery to measure the voltage. The tech probably measured the voltage via the OBD-II port. You can measure the voltage by exposing the positive dedicated jump start terminal in the main relay/fuse box near the inverter and measuring from that terminal to a good ground point, such as one of the nuts securing the top of the front strut mount.

After your car has been off for a couple of hours, try measuring the battery voltage with the car IG-OFF. Then turn on the headlights, see how bright the lights are, and measure the battery voltage with that load applied.

It would not be surprising if you need a new 12V battery if your car really only has 8K miles. That implies it had been driven only <2K miles per year, certainly not enough to keep the 12V battery charged and in good condition. You should be able to buy the correct GS battery from your local Toyota dealer's parts dept for around $160. If the price is much higher than that, then I suggest you call around to the various dealers in your geographic area to see if you can do better.

[jayman]

Of course, the Prius takes a sealed battery, with unique sized posts, and a provision for an external vent tube

Possibly a better battery is the Optima conversion from Elearnaid

Parts kit for installing Optima battery on 2004, 2005, 2006, 2007, 2008 & 2009 Prius

But it will probably cost you more than the GS battery from Toyota

Note: always fully charge a replacement battery before installation, especially a Prius battery

[Blinkn09]

Awsome! Thanks for the replies! I'll attempt to replace the battery myself. Now to decide whether to go with the Optima or the OEM battery. =)

I guess I should have thanked the tint shop for doing me the favor!

[Blinkn09]

Originally Posted by KK6PD

"Well other than that, Mrs. Lincoln, how did you like the Play?"

You will have to drop a note of thanks to the tint shop, of course the battery was already on its last legs.
Consider it a "Mercy Draining."

How did the tint come out. Did you do the front windows, and if so to what level?

As far as the battery, you should be able to find one MUCH cheaper than that, and drop it in yourself.

Good Luck

I have the driftwood pearl color and I chose to go with 25% all around. I love it. It's not too dark and not to light. I'll try to post pictures when I get the chance.

[northwichita]

My advice is to put your battery on a trickle charger overnight and see whether a battery that can start your vehicle can be rehabbed (its not clear to me you've already done this) . Just because I'm curious and because I have the experience dealerships go for whatever will profit them the most. It is an AMG battery which does charge slower I believe than the standard non-AMG types.

[Blinkn09]

Update...I just checked the status of my battery on my prius monitor according to the elearnaid website. According to my on-board computer my auxillary battery is pushing 12.5 volts, so it seems to be healthy even with the lights and other things on. I'm starting to think that the dealer is trying to nickle and dime me. I'll try to bring my prius to a different dealership to see if they will address my ECU update...

[chogan2]

I'll ditto the weak 12v battery hypothesis even with 12.5 v showing currently. Mine did that -- wouldn't start after having a slow drain all night, 12V battery was reading 9V or so. But would charge right back up and pass that test for voltage drop with lights on. I haven't changed my battery yet -- it's not that dead, ... yet. It's on my to-do list.

The only way to know for sure would be to replicate the incident and check your battery voltage when the car won't start. And you'd have to have a way to check the voltage before you started the car. But given the circumstances, it's a fair bet that a) it wouldn't start because there had been a long slow drain that dropped the voltage too far, and b) your battery isn't quite deteriorated enough yet to flunk the "voltage drop with lights on" test.