Help needed with warning lights for '05 Prius

1. Does the MFD display a warning icon in the upper left corner? If yes, pls take a photo and post.
2. Check the inverter coolant reservoir for fluid turbulence when the Prius is READY. If you do not see this then the inverter coolant pump has failed and that is the root cause of your car's problems.
3. If the pump is working and you wish to DIY further then you will need to acquire Mini VCI so that you can read the diagnostic trouble codes logged by your car.
4. The traction battery fan is likely the sound that you are hearing from the back seat, the intake vent is on the right (passenger) side of the rear seat back. That fan will run as the traction battery heats up, more often in hot ambient temps.

 

AND......after sitting for 2 weeks, your 12V battery may have finally died.
IF it is the original OEM battery, it is PAST due for a new one at 9 years old.

When the 12V goes bad it can make all kinds of strange things happen.

 

how many miles on her?

 

The best thing to do is to have the codes read and see what comes up.

How is the car driving/running? Is it still getting good (40+) mpg? Is the fan constantly on or intermittent? When viewing the "Energy" display, does the battery go from fully charged to discharged very quickly (ie 30 seconds or so) and back up to fully charged?

I'm not sure what caused this but taking in the totality of the situation, I believe your 12V battery was low (and needs replaced) and that is known to cause all kinds of problems. Like we say in the electronics world, a bit got lost in the bit bucket. If it were me, I would disconnect the 12V battery, recharge it and see what happens (after reading the codes of course, once you disconnect the 12V battery, the codes will be lost).

 

It should NOT be necessary to disconnect the battery if recharging with a small charger......as long as the car remains OFF.

It might be good to do that to clear codes though; some can stay set and continue to adversely affect operations.

 

The icon showing the outline of a car with an ! superimposed means that the hybrid vehicle system has a problem. Well, you already knew that.

It doesn't hurt to make sure the 12V battery is in excellent condition, but I believe your car has more issues than that.

 

There is no routine maintenance that affects the battery.

9 years is a LONG life for the 12V battery, in a hybrid especially.
The 2 week rest just pointed out that it was past it's useful life.

The surprising thing is that it lasted THAT long.

 

Check the oil level to make sure it's not overfilled from your recent oil change.

 

From the 2005 Prius manual (regarding battery charging):

During recharging, the battery is producing hydrogen gas. Therefore, before recharging:

1. If recharging with the battery installed on the vehicle, be sure to disconnect the ground cable.

2. Make sure the power switch on the recharger is off when connecting the charger cables to the battery and when disconnecting them.

Caution:

• Always charge the battery in an unconfined area. Do not charge the battery in a garage or closed room where there is not sufficient ventilation.
• Only do a slow charge (3.5A or less). Charging at a quicker rate is dangerous. The battery may explode, causing personal injuries.

Given the age of the battery, I'd say charging it up should only be a temporary measure. The battery should be replaced. Given its age and the possibility of being fully or near fully discharged, the battery may not hold a charge.

Good luck!

 

If you have a newer AGM type, sealed battery, that part about hydrogen gas doesn't apply......as well as the part about ventilation.

I don't understand the part about disconnecting the negative battery cable but am willing to admit that maybe the authors of the manual know something that I don't.

I'm sure that I won't be bothering to do that........mostly because my charging, if and when needed, will be done from the access points under the hood (which I think I remember are not present on older models ??)

 

Alot of times the car tech at the dealer will leave your door open and run the 12 volt real low while they service the car. Its easier for them, as they don't need to grab in & out door handles with greasy paws. Thats why many people complain of poor mileage after servicing becasue the 12 is flagged. Normally would not bother a good condition battery but yours may be borderline to start with.

Like Pat said your car is showing classic signs of Hybrid Battery failure. Failure meaning probably one or more of the 28 modules has gone soft and is out of range form the other batteries. This is know as delat and the VCI software has many parameters it can check for Hybrid Battery health.

 

This is possibly a late reply but -
I had same problem with my Nov 2003 Gen II about 3 years back. I replaced the 12V battery. Car was perfect after that.
So would recommend replacing the 12V before doing anything else.
It's not hard to do, once you find where it actually is!

 

I agree that most owners would not bother to perform that step. However, the reason for that precaution is to protect the Prius electronics in the event the battery charger produces excessive voltage or the driver does something ill-advised during the charging process.

A good example of an ill-advised action would be to use the 50A or 100A "engine start" position on the charger which will pump a high current (which requires a much higher than normal voltage) into the 12V battery in an effort to quickly charge the battery. That might cause damage to the Prius vehicle electronics that remain powered up.

Another example of an ill-advised action would be connecting the charger cables with reverse polarity, if the charger does not have a safety feature to recognize the battery polarity has been reversed.

 

I got similar warnings but in a different condition. Here is sequence of events:
- I drove around 100 miles (almost all highway driving ) in the morning to another town without any incident
- Same evening on my way back when I applied brake to exit from highway (almost after 80 miles of highway driving) suddenly, all
the warning lights came up. Just like Scott described. I believe there was a note suggesting to park the car on even surface. (I should have taken the picture but I was in panic mode). I was driving with kids and it was almost going to get dark.
- I parked the car and called AAA to tow it.
- Before AAA could come, I tried to see if the car starts. After couple of tries, may be 10 -15 minutes later the car started normally. I asked AAA to be standby while I started to drive home slowly. Again, after 15 miles or so, when I applied brake, this time only the brake, VSC, and
the "car icon with !" came on. I stopped the car in a Walmart parking lot and checked all the fluid levels. Brake fluid, inverter coolant, and engine oil level were normal. I could not smell anything that will indicate some overheating.
- I waited for 10 minutes or so and drove home.

- Next day, I looked up this forum and went to car parts shop and to get the code read. Surprisingly, there was no code. So, I went ahead
and bought the ScanGaugeII from the store so that I can use to read the code next time. The ScanGauge II also indicates that there are no
codes.

- So far I have driven around in the town around 15 miles one way trip without any warning light.

Some notes:
I have 2006 Prius and it had 93K miles. I have a brand new 12volt battery replaced by dealer.
The inverter pump was replaced (as part of the recall) 2 years ago.
When the car is in "ready" mode, I can see minor turbulence in the coolant tank - indicating the pump is running.
The hybrid battery seems to be charging and discharging normally

I am very puzzled and have lost faith in taking this car for long drive - I do not want to sit in the middle of no where with the family and kids

Questions:
- Does anyone has a confident resolution on "Hybrid System Failure" warning issue?
- Without Scan code can dealer narrow down its issue?
- Does any one has seen similar problem while braking?

 

I have driven about 1000 miles since the "hybrid engine warning ( car sign with ! mark) " light came. I took the car to the dealer as well to see if they can suggest something. The service person was nice - he got the history scanned but other than the auxiliary battery voltage low (which is probably due to the earlier incidence that prompted me to get the aux battery replaced) there was no other code.
I can see the main battery charging and discharging normally.

Now, it is a puzzle - these warning lights came on twice (after the aux battery were replaced)but there is no history of these two incidence.

 

Howdie-

Please start a new thread instead of tagging onto an existing thread because now there multiple posters and it quickly gets confusing.
It's rude to the original poster (OP) and you can see you won't get alot of response.

You wouldn't want someone tagging on your thread would you?

Now to help you,...... the most important part in any dealer interaction with a problem with your Prius is the codes the car throws when it logs a check engine light. It will tell you almost exactly what the car is unhappy about and most times the folks here have alot more experience that even the dealer about how to go about fixing it in the most expedient way possible.

The reason your efforts are not seeing codes are you are using code readers that will not read Hybrid Codes. There somewhat specialized.
A Scangauge reader will not read codes unless upgraded to an Ultragauge.
You can buy a Mini vci code reader on ebay for $25 and use it with your laptop but I don't know your skill set.

Without the codes in hand and posted here its a ........puzzle.

If I was you considering your family issues I would go to the dealer if the car has thrown a Hybrid Warning light and have the dealer read all the codes it has thrown. I assure you if there's a check engine or VSC or Hybrid warning or master warning (triangle) the car usually has thrown multiple codes.
Have them print it out. Most dealers charge one hour labor minimum for this and my dealer for instance charges $130. Don't have them do anything just yet post the codes back here on a NEW POST!
You'll get help.

 

Thank you for response.
I will see if I can get mini vci code reader and start a new post as you mentioned.