What to do after installing new 12V battery?

every situation seems to be different. sometimes you need to press the power button 3 times

 

If you do nothing you “may” have one or two issues that need addressing, but nothing to pressing. The car will for sure be drivable. Things that will happen:

Radio station presets gone
Trip meters gone
Various mpg records (likely) gone

things that “might” happen:

window auto-up may need reteach


First start up possible issues:

push to start may take a few extra attempts


3rd gen issue I’ve noticed, may happen with 2nd gen too:

odd engine rev-up, after start up, for a few seconds. Just for 2 or 3 times

 

From my experience disconnecting my 12 V bat many, many times in a 2004, 2005 and 2008 Prius, I recommend proceeding exactly as for a normal start - foot on the brake, press and release the power button. Wait a few seconds - 10 to 15 maybe, but just be patient. You'll see the gas quantity sorting itself out, maybe a warning light or two. Then, again with foot on the brake, push and release the power button again. Car should power up just like normal. No sweat.

 

Just to eliminate any confusion............here are the Toyota Repair Manual directions (at bottom of post)
.
"CH" has the procedure for replacing the battery.

"IN" has the initialization procedure for the driver window on PAGE IN-34 (not IN-32 as directed by CH)

You will lose radio presets.

You will have to press the power button 2x to clear the dash alarms.

The fuel gauge indicator will go to one flashing dot and it will recalibrate itself in a few minutes. Sometimes I've seen it take hours and miles of driving. Sometimes 2 minutes.

There is always the risk that the car may not start. This is because there are inputs to the engine ecu that change over time due to wear and tear. During normal operation, the ecu 'learns' these changes and adapts. When you remove all 12v power, the ecu 'learned' values all return to the original default values. If the difference between the previous 'learned' value and the default value is too much, the engine may not start. The one that most often (but still rare) bites you is the throttle body position. This slowly changes due to carbon buildup, etc which may hold the blade open a small amount away from it's original clean 'closed/idle' position. If this happens and the engine 'fails to start', it can normally be resolved by performing a good cleaning of the throttle body so the closed position of the blade returns to the 'when new' position.

 

Repair Manual grab:
============
INITIALIZATION
WS–9
1. RESET (INITIALIZE) POWER WINDOW REGULATOR MOTOR (for Driver Side)
NOTICE:
Resetting the power window regulator motor (initializing the pulse sensor) is necessary if: 1) the battery terminal cable is disconnected; 2) the power window regulator master switch assembly, wire harness, power window regulator switch, power window regulator assembly and power window regulator motor are replaced or removed / installed; or 3) the PWR H-fuse, FR DOOR fuse, GAUGE fuse and ECU-IG fuse are replaced. If resetting is not performed, the master switch assembly will not be able to operate the AUTO operation function, jam protection function and remote UP / DOWN function.
(a) *1: Turn the power switch ON (IG).
(b) *2: Open the power window halfway by pressing the power window switch.
(c) *3: Fully pull up on the switch until the power window is fully closed and continue to hold the switch for at least 1 second.
(d) *4: Check that the AUTO UP / DOWN function operates normally.
If the AUTO UP / DOWN function operates normally, reset operations are complete. If abnormal, follow steps below.
(e) Disconnect the negative (-) battery terminal cable for 10 seconds.
(f) Connect the battery terminal cable.
(g) Perform steps *1 to *4 again
===========

And screen grab:

 

NO. NOTHING.
Except for "driver preference options", like radio station pre-sets.
Anything associated with how the car actually works should take care of itself in the first few hours or days.

 

Your model might not even have that feature.
See your owners manual.
And don't worry about "things" until you notice that they don't work exactly they used to.
There very likely will be VERY few that need any attention.

 

I like to check the physical install after the install is completed before starting.

check the battery voltage across its 2 terminals with a DVM. Take note of the exact voltage.

then I check the front jump point under the hood to ground. Should be a .5
Volt drop from front to back as the battery has 8 connections and a long thick cable before the voltage gets up front to the main fuse box.

 

Also it’s good idea to check the battery before leaving the store. Bring your DVM to the store with you. If it’s lower than 12.6 volts ask for a fresher one.
And check the date on the battery.
My dealer has dropped the price on the oem battery to $225.

Then and this is just me when I have the time I put my nice new maintenance charger on it And see how long it takes to light the green full light. Remember that as that’s this batterys bench mark for health. As the years go by and you throw the
Charger on it periodically you can watch how long it takes to charge. If all of a sudden it’s taking much much longer it’s now suspect.

This has worked really well for me over 14 years of ownership and mama has never gotten stuck with a dead 12 volt battery and it’s resulting hilarity. It takes a lot of pro activity But pretty quick to attach a charger on the front jump
Point.

you do not want a dead 12 volt battery in a g2.

 

For next time:

12 volt retailers sometimes have electronic load testers, a step up from volt meter. They’ll use it when assessing customers current battery Ask and they’ll likely test the battery you want to buy, for free. You can also DIY the test, with something like Solar BA9.

 

I'll be happy if it passes the volt test much less a load test. Which is probably 100% more that any other customer demands that walks in.



Its easy to take the front underhood fuse box cover off.

Along the top edge of that box push in the bottom part of the box thereby relieving the catches that are holding the top over on. All in one motion with one hand along the top of the box push in the bottom while pulling the top off.

Its quick and easy cover will come right off.

Once you have access to that front jump point you do not need to ever go in the hatch again. It only matters what it delivers to the front fuse box.