Prius Won’t Go Into Gear Dead Hybrid Battery Low 12V Battery

If your car was working fine before you let it sit for 2.5 weeks, it should be fine once you put in a new hybrid battery (and possibly a new 12v battery). The cost to replace that can range from dealer to dealer, but it should be no where close to $10000. If the dealer is telling you it'll cost that much to fix your car, then he's obviously trying to sell you a new car.

 

Welcome to PriusChat!!

Sounds like the dealership wants you to trade in the 10k repair job for a new vehicle. Did you get an itemized repair quote?

Do you have some tools and a DIY attitude, or would you be relying on someone else to repair this vehicle?

If your 12v battery is still the original, then best to start by replacing that first.

Not sure if they will sell over the counter, but here is a new OEM hybrid battery for under 2k :

2004 Toyota Prius Battery assembly, hv supply. Electrical, wiring, cable - G951047031 | Passport Toyota, Suitland MD

 

Did you try to jump it when it did not start? Did you measure the 12v battery at that time? If you tried to jump it how exactly did you do it?

 

11.6v?

 

THIS.

The 12 V battery runs the computer(s) that produce the trouble codes.
You can NOT trust the trouble codes that are produced when the 12 V battery is not up to snuff.
AND you can not necessarily trust a shop that won't TELL you this to test the 12 V battery to see if it is bad or not.

You MUST have a good, fully charged 12 V battery in place before chasing any other possible problems.
Unless you just enjoy wasting money.

 

12V 11.60 OFF 14.00 ON

We may be preaching to the choir again but the moderator or the op did not come to synagogue today....

Since we don't know what the op did to try to start it (at this writing) and we don't know if the dealer charged the 12v battery or used a powerful jump pack, a lot of this is speculation.

It would seem logical that 2.5 weeks of non use would discharge the 12v. It is also likely that a jump by the op did not allow the battery to equalize for several minutes as specified in the owner's manual. Which is often necessary with a discharged 12v battery.

In this case, the 12v battery's off state voltage of 11.6v at the dealer does not concern me. I have seen 11v routinely Ready the car without trouble. The 14v when On is low unless it has been running and high amp charging for many minutes. Normally the inverter's charging circuit would output 14.8v under 11.6v off state battery conditions. It is possible the 12v battery was dragging the charging voltage down.

It is likely the 12v battery is beyond its useful lifespan and its 2.5 week starvation diet was the kiss of death. It is also possible the hv battery is old and weak, however it is less likely it won't run if it was working three weeks ago. The brake actuator is possible on this vehicle or could easily be fake news.

Without repairing the ability to go to Ready the rest is just more speculation. But I could see a dealer recommending two batteries and a brake actuator for $10k msrp. Knowing the dealer parts markup is often 100% or more, there is always negotiating room or third party options.

 

Looks like you need to try charging up the 12V first. In reality, 11.6V should be enough to ready the car. But the P0A80 from a weak HV battery block gets in the way. Still, a well charged 12V is a better troubleshooting starting point than a half dead one.

BB1 is lower than the others, so that could be a problem. That's the P3011, iirc. The traction battery for sure needs work or replacement depending on the severity of the condition that triggered the P3011 code. Best fix is a new traction battery or a kit from @2k1Toaster. But before replacing the battery, check that the wiring harness isn't corroded and causing false reading.

 

This is likely another example of a car that had a semi-weak HV battery that had a module dip down from self-discharge during a period of non-use. Quick resolution would likely be to install a fully charged 12v battery and perform a force charge on the HV battery by putting the car in drive, holding the brake and giving it some gas to make the engine/hybrid system throw some current o the battery. Charge it until the purple/blue bars turn green. The car will likely work just fine following hat. If needed, disconnect the 12v battery for a minute to clear any remaining codes.

No 100% guarantee this will solve all your problems, but it is likely to get you back on the road for just the cost of recharging your 12v battery or buying one. At some point in the future, the weak module may rear its head again.

 

Plenty of good answers already on the low battery block and the dead 12V. The parking "gear" as you call it is just a result of the low 12V not having enough power to move the parking pawl into position. Fixing the 12V will almost certainly make that go away.

@TMR-JWAP has the best advice I've seen on this so far.

 

New Hybrid batteries cost way over $2,500

 

Not really, but that may depend on which part of the USA you live in (you didn't add a metroplex to your profile 'Location').

Some dealerships will sell a 'new' OEM battery OTC (over the counter) for about 1650++ (taxes, core deposit, etc).

There is also a few options for "new" aftermarket replacements, one starts at 1600 (total price paid), and includes delivery.

Both of the above options assume that you will DIY install, or have someone do that for you.

 

That depends on what your definition of "way" is.
But that statement is generally wrong.