I have a 2005 Prius, with about 90,000 miles. For about three months, it's been mis-behaving, as follows: WIth increasing frequency, it won't start. Sometimes this happens if it's been stopped for just a few minutes; other times when it's been sitting overnight or during the day when I'm at work. A jump start works -- but I don't think it's feasible to call roadside assistance daily. Other times it starts after a few minutes, with a variety of other things happening, not necessarily all for each time it doesn't start: the clock resets to 1:00; the trip meters and odometer reset to 0; sometimes the radio buttons reset; the GPS resets to Pennsylvania (I otherwise keep it set for California); all the "previous" locations in the GPS are erased; when it finally does start, the MPD (is that the screen that displays mileage, etc?) displays the message "System loading; do not turn off power" with a lovely bluish-green picture that looks like a cross between a solar system and a CD loading; the alarm goes off and pushing the alarm off button on the fob doesn't do anything. Before this annoying habit started, the child lock mechanism failed on the right passenger side, i.e. no matter what I did, that door could not be opened from inside. Now the window lock mechanism isn't working -- passengers can't operate the window switches. Also, the left rear light has burned out three times in the past nine months. The mechanic says the battery is okay. It started this morning, after a brief tantrum, but 12 hours later, it refuses to do anything. Yesterday it started in the morning and the evening, but with the same symptoms as above. The day before it started fine, but as soon as I parked and turned it off, and then tried it again, it refused to start. Thanks for any thoughts, advice, suggestions.
Inspect grounds and the terminal connection on the battery. Sounds like a ground is loose or corroded.
Your car forgetting settings means that you're losing 12 Volt power to the computers. Your battery is 3 years old, and the 12 Volt battery is a known weak spot in the Prius design. I'd bet you a nickle that replacing the 12 Volt battery will clear this right up.
Yes, this sounds very much like a dying 12V battery or failing connections to it. These are easy to check and correct, there's no need to suffer. Was this battery ever drained, for example by having some accessories running with the car in ACC or IG-ON (not ON) for more than a few minutes, or by leaving a door or the hatch open for several hours? The bit about a tail light burning out three times is peculiar but probably a coincidence. Have the repair shop check to see whether some amount of voltage is reaching it even when the car is OFF. If that were somehow happening it could explain both the burnouts and a dying battery.
After you have had your car jumped, how long do you leave the car READY to recharge the battery? It probably needs 2-3 hours or more, before the battery will have accumulated sufficient charge. I agree with the other posters that the 12V auxiliary battery is the most likely cause of your symptoms, and suggest you have it replaced immediately. Since 1) you are losing settings and 2) a jump start is all you need to start the car, this makes it obvious that the battery is the problem. Richard offers a good suggestion about checking to see whether the left rear light might be causing a continuous drain on the 12V bus. Regarding your window problem, it appears that the switch (or wiring) on the driver's inside door armrest that locks/unlocks the passenger window switches is faulty, if you have already tried that switch to ensure that it is in the up position. The child lock problem on the right rear door is a separate issue, and perhaps cleaning and lubrication of the mechanism is all that is required.
I second the battery, and especially the teeny ground wire that goes to the unitbody. The bolt that secures the ring terminal to the unitbody can corrode very nicely. I'm in the habit of backing off and snugging up the ground wire bolt every Spring and Fall Something odd about that tailight burning out like that. When replacing any bulb, it's important to use a clean cloth soaked with iso alcohol to clean the glass capsule and get any oily fingerprints off. The oil on the glass capsule can shorten the life of the bulb, in the case of halogen headlight bulbs it can cause rapid failure Has the car ever been in a flood? Once water gets into the wiring of any car, it's usually a writeoff
If the battery has be LOAD TESTED and checks ok and the connections are solid, you almost certainly have some sort of parasitic current draw that is drawing down the battery as it sits. There is clearly some sort of wiring problem in the door that has caused the windows and lock to stop working, that would be a good place to start looking. As others have said, all the memory losses are caused by the battery voltage dropping. Parasitic drains can happen on any car, and are a pain to find. You can test for them by putting an ammeter in line with that battery cable and reading the current draw when the car is off. If it unusually high you may be able to trace it down by pulling fuses one by one until the draw drops to normal. Be aware that some items like the smart-key system, the car computers and the audio system have some very small draw normally, so you may see small changes when you pull their fuses.
i have 94k miles on mine.. i need to replace the 12v too.. but have yet to do it. as long as my car doesn't sit more than 12 hours.. it's start-able.
