Prius v Display Audio Service Menu w Battery Check

Found this in the c forum and verified it worked on my 2012 Prius v 3 with Display Audio:

Realtime 12v Battery Voltage in Off or Running State

You can easily check out your battery status/charging system by using the MFD Service Menu.

1 Get your Prius into "Accessory Mode" .
-- Press the power button without touching the brake pedal.
2 Put the MFD into "Service Menu" mode (green)
-- Press and hold the "CAR" button on the MFD while turning the headlights on and off 4 times.
3 Press the "Function Check / Setting" field on the screen.
-- "Function Check / Setting menu will appear.
4 Press the "Vehicle Signal" field.
-- "Vehicle Signal Check Mode" screen will appear, showing

Battery 12.2v ---------SPEED 0 Km/h
IG OFF ---------------TAIL OFF
PKB ON --------------ADIM/TCAN BRIGHT
REV OFF

The 12v battery voltage will be listed and changes as load changes.

5 My 2012 v read 12.3 initially. When I turned on the lights it went to 12.4v.
6 Now get your Prius into "Ready Mode" - step on the brake and press the power button.
-- The battery voltage should immediately rise to at least 13.8 volts. Mine went to 14.8.
7 Shutting the car down will reset the system back to normal operation.


To put the MFD into "Diagnosis Check" mode

A Get your Prius into "Accessory Mode" .
-- Press the power button without touching the brake pedal.
B Put the MFD into "Diagnosis Check" mode (red)
-- Press and hold the "SETUP" button on the MFD while turning the headlights on and off 4 times.
C The red "Diagnosis Check USA" screen will appear.

 

Don't recall. Never used it but it's easy enough to get there.

 

Here are the first and "next" pages in the Diagnosis Check (not Service Menu with battery check) mode. I did not try "init" or "mem clear". The dark black buttons function.

 

A quick update on the procedure above:

It is not necessary to be in the Accessory Mode for this to work.

You can also do this in the On mode (allows Windows and Fan loads) or the Ready Mode (eg running) by simply pressing and holding "Car" while cycling the headlights 4 times.

Then "Function Check" and "Vehicle Signal Check"

 

The only way I can get it off is to power down the car. However, all the head unit functions that operate from the steering wheel still work.

 

What method did you find to keep the engine on? I know you can force charge it by holding the brake while in drive and giving it some gas. Slightly dangerous if you were to release the brake.

 

Actually the engine won’t idle, run continuously or force charge in park. You can give it gas in Park and it will run without charging. Using max ac won’t force the engine on either as the entire ac system including fans is electric.

You can force charge with the brake depressed in drive by pressing the gas. It will charge the hv battery quickly and is the method used by the Dr Prius app to estimate the hv battery life.

 

I did try it. It did not work. The AC compressor is a highly efficient three phase inverter driven scroll unit that does draw a fraction of a kilowatt but nothing like the kilowatts the motor/generators can put out even at idle.

What I don’t like with the Prius’ idle recharge algorithm is that it just barely adds enough charge to run the electrics for a few more minutes. At that point the engine has to start again. This causes excessive start charge cycles in my opinion and leaves the battery at the low end of its charge when the vehicle is subsequently driven. Normally the charging algorithm keeps the hv battery well over half, usually over 75% charged. Its not like these models have predictive terrain algorithms like new hybrids have to maximize regen. I believe this behaviour was introduced when Toyota updated the inverter firmware in an attempt to reduce failed inverter modules in these models.