2005 Prius- !, check engine and other lights on

unlikely, but it's worth checking. the 12v can make funny things happen, but the fan and driveability problems are usually related to the hybrid battery.
it's alway worth checking the cooling fan as well. that and the 12v are easy.

 

If the HV fan is always on the HV battery may be over heating. May be a sign of bad cell within the HV battery.

 

This belongs in the Gen 2 Forum, I believe. Probably not 12V battery related, but worth a health check given the miles/years. Very important to make sure the traction battery cooling vent is not blocked or clogged with debris. After all that, you need to report how the traction battery holds state of charge. A failing traction battery from Gen 2 will swing quickly from low (purple bars) to high (green bars) and vice versa under load/no load conditions. Quickly means a mile or two of coasting will take the battery full green or a mile or two of climbing will run the battery down to purple. It would not be a surprise that a 2005/2006 with 160K miles has exhausted the traction battery.

 

Where are you located? Seems to be a battery failure

 

If the 12 V battery is over 5 years old, that would be a good place to start.
After that, you probably need a shop to do a diagnostic before you decide on the next step.

 

chris, why did you post 2 threads about the same thing? i'll report it for you.

 

if you don't fix it sell it on craigslist, its worth more than junk.should bring 1200 if its in good shape...odds are you need a HV battery rebuild, sometimes its only one module you can buy on ebay for $30. if you don't want to do it yourself it should cost around 400 to rebuild at a shop, check around

 

NOT a good assumption.
With no load, it should read 12.6-12.8 if fully charged.
12.0 is only about 40% charged and is NOT good.

 

I can understand you clutching at straws, but in reality, no, it is very unlikely a bad 12 V will cause the fan to run.

No lights are on as the system's thresholds have not yet been met. But they probably are not far away.

If the fan is running at an audible speed, the HV battery is running warm/hot. This is one of the precursor signs of HV battery failure. You could check the HV cooling fan to make sure it is not clogged with lint/pet hair. But other than that, you should be saving so you can have the cash to replace the HV battery in the near future.

 

Yes, this fan problem has nothing to do with the 12v battery. You can check the 12v health, but a bad 12v would not make that fan go on

 

I would take it, as there's always value in a car with tons of usable parts.

I'm sure you can sell it on CL if you really wanted to. Even with the bad battery, it would fetch at least $1000.

 

You don't know until you try. Nothing ventured, nothing gained.

 

You don't KNOW that for sure.
The computer that senses HV battery temp is just as prone to getting false reports when the 12 V is weak as any other part of the car is.

I certainly would take a $200 gamble on a 12 V before I'd gamble $2000 on a HV battery.
Actually I wouldn't do either without some tests to get at least a clue as to what the REAL problem is.

 

The car doesn't require the use of the 12v battery when it's on. You can disconnect the battery and it'll operate normal. So you can be certain the fan is not caused by the weak battery while the car is in ready mode

 

Unless the converter ( charging system) is also not working right.
Without a good battery in place, minor fluctuations in the converter can become BIG fluctuations.