2004 Prius Died - HV Battery Failure?

Buy AAA plus, and a Cell phone. Take off where ever you need to go. IF the car fails, then count on renting a vehicle and dolly to tow it to San Diego.

Ideally,, give it a few days of running around, take a long,hot day drive as an experiment. (I also would have the tech take a good look at the inverter coolant pump!)

Icarus

 

MDooley:

Are you still running the original 12V battery?

 

Hi mdooley,

Sounds like a fuel issue to me. I had a Tempo which would conk out after about an hour. Went through everything. In the end it was due to an fuel pump (down in the gas tank) that would eventually cease up after an hour.

If you want to do a shotgun repair, which may not be it, but could have a good chance of getting the problem - get the throttle body cleaned, get the 12 V battery replaced (intermitent cell short?), have the fuel filter replaced and get the fuel pump replaced.

It may very well be fixed as is though - and the problem was dirty/loose 12 V battery connection.

 

5 to 6 years in a hot climate is a long time. Contrary to popular perception battery capacity goes up with higher temperatures and down with colder temperatures. (Thats why you need good batteries in the winter, it's not that the batteries are an worse,, it is just basic battery chemistry and the battery has to work harder to turn over cold, thick oiled engines).

On the other hand battery LIFE goes down as the temperature rises. In rough numbers for every 10 degrees F that a battery has to live in (above ~70f) the life expectancy is reduced by ~10%. Add in vibration which is also a battery killer, and five years is a long time.

It is no coincidence that batteries tend to be warranted ~60 months, as that is where the majority fail. It sort of averages out, colder climate makes the battery work harder but live longer, equalling 5 years. Hot climates batteries don't have to work very hard,,but they are hot,, averaging, about 5 years.

Probably the best source for battery technical info:Car and Deep Cycle Battery FAQ, Battery Manufacturers and Brand Names List, and

Icarus

 

In a Prius, it's the same assembly. They're not separate parts, so you replace both at the same time.

There is no external fuel filter on a Prius. When car makers went to "returnless" fuel systems - due to evaporative emissions - the filter was made integral with the pump

So if you get a tank of bad gas, cha-ching!

 

12 volt battery I think. Also throw some fuel injector cleaner in the tank. I had some water in the gas once that did something like that. Fuel filter fixed the problem.

 

At least now the dealer knows you are not a whacko!

Icarus

 

1. Enter diagnostic mode on the MFD and look at voltage from the 12V battery. Not sure how to do that on your MY.

2. Buy a ScanGuage II and use it as a monitor. It can also read & clear some of the Diagnostic Trouble Codes.

 

the tech was just going on what the car spit out as trouble codes. the loss of 12v power when your accessory battery quit resulted in a loss of the original codes. short of reproducing that situation, the tech could not have known the cause of your problem. because the car couldn't report it.

so you're going to fault him for evidence-based diagnosis in the absence of evidence? (and the presence of misleading evidence?) there was nothing more they could have done. maybe drive it a little longer after the HV recharge, but there is a line to draw when one is reasonably sure the problem is fixed. customers get pissed off when techs put miles on their cars. techs don't get paid for the time they spend driving around, but a problem coming back not fixed does reflect negatively on their work records, so they try to strike a reasonable balance.

so just consider what the guy had to work with there before you fire off your complaint, ok?

 

it's not the 12v battery. you can disconnect it and the car runs fine.. because the hybrid battery supplies a charge voltage to the 12v line. if it shorts, the car turns off and drops the parking pin... you'll know if that happens. if it drops below 10 volts, it blinks lights on the dash but doesn't function... there is no way for the 12v line to fail though.. unless the 12v inverter failes... but were back to the codes at this point. they don't imply the 12v inverter failing.. they imply a fuel line clog.. or.. something...

so... odviously.. did they check the fuel pump and all of it's connections. it really does sound like a fuel, fuel line, or fuel filter problem.

galaxee: codes dropping off with the 12v line?... i pulled spark plugs in a particular order, disconnected the 12v, and still pulled codes...

 

so your topic title "2004 Prius Died - HV Battery Failure?


can be edited to "Re: 2004 Prius Died - cooling pump failure!"

no HV battery problem.

 

Ming: Thank you for a very clear and complete description of the problem you experienced. I really appreciate it.


So let me see if I can describe the scenario.

The inverter coolant pump failed. The car was driven into town successfully without any indication of a failure. But during the trip, the inverter overheated to the point that it stopped charging the 12V battery. Still no failure indication. The car continued to operate the 12V system off the battery, drawing it down to the 10V range. Car arrives in town, and is shut off. The inverter cools down, and is ready to run next time it's called upon.

An attempt to start the car fails. The drawn down 12V battery is only putting out about 10V, which isn't enough to get everything running. The VSC computer isn't getting enough power, and raises it's error indication. Some other computers also raise error indications, but they're not critical to getting the car moving. An additional attempt at starting the car just barely succeeds, and the cooled down inverter recharges the 12V battery. Some of the error indications are cleared after the 12V system is functioning again.

The car is driven home, and the same scenario occurs. The inverter fails somewhere on the way home, but the 12V battery still has enough power to continue operation of the car. But the computers are being starved for power, and store a number of off-the-wall codes.

The car is driven to the dealer (well, most of the way). It's a longer trip, and the 12V battery just doesn't have the capacity to operate the car that far. So when the voltage drops below about 10 volts, various computers drop out and issue their error indications. The radio didn't have enough voltage to it to react to the power button on it. The computer that reacts to the car Power button didn't have enough voltage to process the Power OFF request. The computer that controls the door locks didn't have enough voltage to operate the locks. Since the car couldn't be turned off, the remaining systems continued to operate until they dropped out for lack of enough voltage. The high voltage battery continued to be drained until there was a total system shutdown.

The car was towed to the dealership with all sorts of error indications, a low 12V battery, and a very low high voltage battery. The inverter cooled down, and was ready for the next round. The tech recharged the high voltage battery, and perhaps the 12V battery. With the power restored, the error codes all cleared and it looked like everything was functional again. At least as long as the inverter wasn't overheated by operating without the coolant pump.

When it all happened again, a more exhaustive search identified the bad coolant pump. Even though there was plenty of gas in the car, the computer monitoring the fuel level had been confused by the low voltage on the 12V system. False alarm, but fodder for a finger pointing contest.

Replacing the inverter coolant pump corrected the basic problem. The inverter apparently survived its ordeal, and all the error codes cleared up.

I think the 12V battery is still on its last legs, and should be replaced now. Five years and 120,000 miles is already a long life, and there can't be much left of it. Since it is only required during the car startup sequence, problems with it will only be noticed at that time. The problems can be a variety of error indications from whichever computers are the least tolerant of a low voltage condition. If there are error indications from, for example, the brakes and the radio, then both of the indications are false. The problem is a weak battery.

Frustrating as the whole sequence must have been, the actual damage to the car was probably just the failed coolant pump. Complete failure of the inverter would be a real owie.