Hybrid System Warning Light + Yellow Brake Warning

Hi all,

I've got some issues with my 2005 Toyata Prius (~150,000 miles), and I hoped someone could help shed light on them. My wife was driving recently and the "Master Warning Light", the "Hybrid System Warning Light" and the yellow "Brake System Warning Light" all came on.

Some quick reading of the owners manual said we should take it to a dealer right away, but because it was a yellow, and not red, brake system warning light it seems ok to drive at least to a dealer. in regard to the yellow brake system light the manual said it could be that: "the regenerative brake system failed or that the hydraulic brake system failed"

With that said, I don't want to blindly bring it in to a dealer without having at least some clue as to what's going on. Does anyone have any experience with these warning? Can you suggest what might be the problem or any tests I could do, or that I could ask the mechanic to do?

Now, I have a cheap bluetooth OBD reader hooked up to the "torque" app on my phone and I thought I would try to see what error codes there were to learn more. But strangely, it did not read any fault codes. I've used this reader successfully on my 2001 Mitsubishi galant, but I'm not reading anything for the prius in this case. I'm not sure if there is legitimately no error code associate with the warning lights or if my app is just failing to read them for some reason. If anyone has any ideas about this as well, please let me know!

Thanks in advance for replies!

 

Hello again,

Thanks for the replies all. I took the car to the local parts store to see if they could read the errors that I couldn't and it seems there is something with the ABS system. Unfortunately they guy reading my errors for me was in a hurry and didn't let me see and write down all the codes, but there were no normal "engine" fault codes, but his device loaded an "ABS module" and there were a few errors on this that I just saw at a glance. There was something about relay 1 and relay 2 and a message that said something about a "capacitor malfunction".

I'm now following nh7o's post and I'll attempt to get the ABS system to flash me codes. Maybe that will give me an idea of exactly what's going on?

ericbecky, I'm located on long island ny, and my batter is old. As far as I know, it was never replaced and i'm running ~150,000 miles. Is the battery something I could test on my own with basic circuit knowledge and a multimeter? or do I need to actually take it to a place? Or do you think the ABS errors could mean this is not a batter issue at all?

Thanks again so much for the help! I hope it will give me some much needed savings on repair if I can know the problem going in instead of just taking it to a place that may or may not be experts on hybrids and doing what they say blindly.

 

One more question, just a general thing, can anyone tell me where to look to find good hybrid mechanics listed for my area (central long island, ny)? I'm having trouble finding a good listing.

Thanks!

 

Ok, so I've checked the 12V battery and the ABS blink codes.

The 12V Battery seems OK. It's putting out a solid 12.20V when I check with my multimeter. Is there anything other than voltage output that would point to the battery being bad?

As for the ABS blink codes, I shorted pin 13-4 on the OBD DLC connector and got the warning lights to blink. But i'm having a bit of trouble deciphering the blinking. As I understand it, I should expect the 2 lights to blink different amounts of times to indicate the values of each digit of the 2 digit ABS code, then a pause, then blinking again for the next code. This did happen, but the blinking between the digits seemed very sporatic and I couldn't tell when pauses were happening between different code blinks. It was like the timing of pauses between codes was not synced between the 2 lights and I often couldn't tell a difference between pauses between blinks and pauses between seperate code digits.

All that to say, can someone help me decipher my blink codes? I posted a video of the blinking on youtube:

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If anyone could help me figure out exactly what codes I'm getting here, I'd greatly appreciate it.

As always, thanks so much!

 

Ah, I see. Yes, this was 12.2 V with nothing on; just opened the hatch with the car off and probed the battery terminals directly. I do have a trickle charger, so I'll set it up to charge the 12V battery and see what that does for me.

Thanks again for the replies. Your insight is invaluable, and even if this is a simple standard problem, I'm learning a whole lot I wouldn't know otherwise and probably saving myself a good bit of money by avoiding a mechanic. Thanks! =)

 

I've charged my 12 V battery witha trickle charger. It now reads just above 13v resting not hooked up to anything. Is this a better range? I'll try it in the car again in the morning. Can anyone tell me what voltage range to expect resting? This will help me know if it still doesn't work if it's just a bad battery to replace or if I should look to other problems.

 

nh70, you're a champ for walking me through all this =)

I haven't had a chance to do the voltage diagnostic you suggested (I'll do it in the morning for confirmation), but after I trickle charged the battery and put it back in the car and all the errors went away. I drove to a destination 30 min away and everything was fine, but when I started the car again on the way back, all the warning lights came on again. I assumed this meant the battery was bad so I took it to the parts store and they tested it their tester also said it was bad.

So assuming I do in fact just need a new 12V battery, can anyone advise me on where to look for one? My parts store (AutoZone) could order me an Optima brand Model 46B24R but this costs $215.00 . That seemed a little steep to me. Can I find a replacement cheaper? If anyone has brand or store suggestions for where to look, please let me know.

P.S. On a complete side note: I've done it a couple times now so I'm used to it, but it sure is a pain getting the battery in and out. All the screws on the brake power supply and what-not in the way. I don't get me started on the time I accidentally let the hatch close after taking the battery out so I had to crawl in from the seats and stoop down to put the battery back in before I could open the hatch again. Shesh!

 

Ok, great. I've done some searching and found an Optima D46B42R on streetsideauto.com for $147 with shipping. I ordered it and it should arrive soon (not by drone unfortunately =P ). I assume this will finally solve my woes. I'll do one more post to confirm after i get the new battery in.

A special thanks to nh70, ericbecky and cyberpriusII for your awesome help and advice. I learned a lot and saved a bunch of money, thanks! You've definitely sold me on sticking around the priuschat community. See you around!

 

Alas! My Saga is not over~!

Let me recap my situation breifly: I had crazy warning lights, which pointed to a bad battery. I took the battery out, charged it, and put it back in and the lights were gone but only briefly. I took the battery to get tested at the parts store and they said it was in fact bad. So I ordered a new one, got it shipped, charged it fully before putting it in (to be sure), put it in, and everything went back to normal.....but again only briefly!

After a bit of driving, the warning lights came on again! x_x

Being scientifically minded, I wanted to go back and double check things again systematically. So I took my original battery back to a different parts store and asked them to check it again, and then I was going to get the new battery tested too (in case it was defective). But this time, the original battery tested as good. Assuming, the new battery is also good, this means I have another problem!

My first thought was the alternator. I'm not sure if the 12V battery on a Prius works the same as a traditional car where the alternator running is what recharges it. But it naively makes sense to me that if the alternator is bad, the good battery would eventually run low on it's own causing the warning lights to come on. The guy at the parts store kindly offered to test the alternator for me, but not sure if we did it right. I'll explain what we did and those with experience can please tell me what they think: We hooked up the voltage testing unit to the battery terminals under the hood (the positive in the fuse box and the ground terminal on the body nearby) and I turned the prius on, but the gas motor wasn't on yet and he was reading no voltage. I cracked up the heat because that usually engages the gas motor, but still nothing as the gas motor wasn't really revving. So I put it in neutral and reved a bunch, and he got a small increase in what he called the "ripple voltage" but still ~0V read.

Is the result of this test normal? did we do it right? Should there have been a voltage of around 13V from the alternator with the engine revving like a normal car, or is that just not how it works on a prius? Also, an important side note, it's possible he wasnt' making a great connection with the positive terminal. His clip was big and wouldn't fit in around the terminal in the fuse box, so he just manually pressed the end against it. I figured it was sufficient connection however.

If anyone has insight in to what might be going on, please let me know! If it's just an alternator, I'll look to get a new one and replace it.

Thanks everyone!

 

First , thanks for the education Patrick Wong. I took a look at my voltage levels and inverter coolant and here's what I found. The voltage levels seem ok, high if anything. The terminals under the hood read 14.03V when the car was "Ready" and read 13.0V when the car was off. I took a look at the inverter coolant reservoir and it was a little difficult to see through the plastic container, so I couldn't tell if there was any turbulence or not, and the gneral level seems perhaps ok, but perhaps a little low (maybe 1cm low at most? but the full and low marks on the outside seem very close so maybe this is some issue there). Generally though, I've driven the car with the new battery in for a week or two (on just a short commute not every day) and I havn't seen any sign of the battery giving out further. This combined with the fact that the voltages are OK makes me think the battery, and perhaps inverter, are working. I suppose it's still possible the coolant pump is not working and once it gets hot, it would stop producing voltage. If anyone can suggest a further test I can do on this, let me know.

With all this said though, my wife finally took the car to at least get looked at at a mechanic. They're not hybrid experts so they couldn't do much or offer too much insight, but they read the error codes. Unfortuantely my wife didn't get the exact code, but she said it had to do with the "Battery Control System" with an error code of something like "1130" (this was the best she could remember, but said it for sure had 11, 0 and 3). Some quick google searching hasn't yielded anything that looks particularly applicable yet.

Anybody have further insight they can offer me on this? Thanks yet again in advance.