Repeated 2009 Battery/Starter Failure

Prius does not have an alternator.

I am as stumped as bisco & Mendel. At least I am in good company.

Pop, as long as you are on the deck, is the hatch light turned off?

 

I agree that you need to seek professional assistance and recommend you visit your local Toyota dealer or an independent that specializes in Toyota hybrids. Do not expect an untrained mechanic to be able to figure this problem out.

Since you say that you can turn on the headlights OK and the 12V battery voltage is reasonable (although a bit on the low side), the door locks are inoperative, and the problem seems to come and go, you may have a problem with the body ECU. What is needed is to retrieve any DTC logged by the various vehicle computers to provide a clue about what is wrong with your car.

I understand the car is in a parking garage right now. If you can crawl into the hatch area along with a good flashlight, one thing you might try is to disconnect the 12V battery, check the tightness of all cables, then reconnect.

Once you are in the hatch area, remove the folding hatch floor. You will see the black plastic tray above the spare tire. At the center rear of the tray you will see an access panel. Open that panel and you will see the mechanical hatch lock release. Move that release and push up on the hatch to open it.

Now you can get out of the hatch. Remove the black plastic tray above the spare tire. Remove the trim floor panel above the 12V battery, right rear corner of the hatch floor. Check the tightness of the positive cable. Check the tightness of the negative cable. Use a 10 mm socket to tighten as needed.

Unbolt the negative cable where it attaches to the body. Leave disconnected for a few minutes to clear existing DTC. Then reconnect the negative cable to the body and try to start the car. If that works, that may save you a towing charge from the parking garage.

However even if you are able to get the car started using this method, unless you found a loose battery cable you should assume the problem will recur.

 

I've accidentally drained the 12v battery a couple times. In each case I put a battery charger on it at the underhood jump connection . It took less than 5 minutes charging to have enough juice to power up the car with the charger connected. As soon as it powered up, the ICE started from the HV battery and the inverter brought the system up to 13.7v instantly from a DVM measured 11.7 prior to the charger install.

I'm wondering if the inverter that charges the 12v system could be the problem with the issue topic.


iPhone ?

 

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