Entering Maintenance Mode (aka 12V Battery Check) without Switching Headlights ON/OFF

Well, just tried this - and it doesn't work on a 2009. The image above does not match the MFD for an '09 either. There is no "box". There are two horizontal lines (on a black background, not the multi-shaded brown), that go from one side of the screen to another - and no side lines. I still tried the above, touching in the spots indicated - and it didn't work. However, the other method mentioned above Weird stuff happening? MPGs dropping? Test The Battery | PriusChat worked just fine, and immediately. And, it would seem, much simpler to get to the maintenance screen.

 

I have a 2008 and although the display is different to that shown above it is still possible to do this by touching the screen in the same pattern just inside the gold lines at the left hand end of the screen.
The problem with turning on and off the headlamps is that it is hard on the bulbs particularly if you have expensive HID headlamps. Turning the headlamps on and off also lowers the readings you will get.

John (Britprius)

 

Still didn't work. I may not be hitting the right areas - but the other method is much simpler and quicker. And I like the idea that you hit the headlights, might bleed off some "topped-off" charge if the battery is marginal.

 

I can vouch that it does indeed work on the Gen II Prius. I've had two different Gen II's and it worked on both. I would say you are doing some thing wrong.

From memory, you start on either the consumption or energy screens -- doesn't matter which, although the consumption screen is better as you have the grid layout of the graph.

You press the screen six times in reasonably quick succession - top, bottom, top, bottom, top, bottom.

Let us know if you have success and what you were getting wrong.

hope this helps.

PS, to cancel when you're done you can press and hold the Display button for 6 seconds until you see the start up screen.

 

Go to 1:20 in this video:

to see where to press. Sorry for the shakes.

 

Quoted below OP of thread. Yeah this is indeed more cool. Very simple to do and can be done by a passenger while driving too. You can enter it using this method in any of the 3-4 conditions, 1 push on 'start' button or 2 start button clicks, and while holding the brake and pushing 'start' for full run. 4th condition while operating too. hold 'Dispaly' and 6 touches on top and bottom as example shows; '1, 2, 1, 2, 1, 2' and you're in. way more simple than the light trick.

 

Now, my battery is 7 years old, and after driving 20 minutes home tonight, it reads 12.4v with no load, and 12.3v with the headlights on. I've used a 1kw inverter on camping trips to power a small microwave and rice cooker, so the battery has gotten a good workout. I'm really surprised the battery has lasted so long.

 

Hey, that's really good to know! I hadn't found that in the manual, and I used to think I was stuck in that mode until I turned the car off.

I just confirmed it works that way in my 2010 (with the original 2010 nav). I also picked up a 2012 nav (with the idea of putting it in the 2010, looks like a drop-in but turns out will need a gazillion wire terminal rearrangements, unless someone sells a prebuilt adapter harness I haven't found yet).

Anyway, the 2012 one doesn't have a Display button (it has Setup instead, and then Display is a soft button that appears), but I see that a long hold of Setup does the same thing.

Also, I find that the six-touches method still works on my real 2010 unit, but I have not been able to make it work on the 2012; only the taillight method is working for me. However, this is just on a shelf, hooked up to a battery; maybe I am missing a signal from the car, and the six touches would work if it saw the parking brake applied, or something.

It might be easier on those expensive HIDs to just turn the switch to the taillight position and back. Only the taillights are wired to the nav unit (so it knows when to light up its buttons) so that's what the enter-maintenance trick cares about, not whether you go all the way to headlights.

-Chap

 

Tonight I tested the battery again, after the car sat for 20 hours, and the temperature is dropping to 43F outside. With only the dome lights on, it measures 12.12v at the battery, and adding the headlights on for a load, 11.82v. So, yes, I'm starting to think about replacement after 7 years. I've been very happy with this battery.

I notice that the battery space looks like it could accommodate a much larger battery, almost twice the depth. Anyone have any thoughts about putting a larger battery in there? Once charged up, would the inverter run less often?

 

After letting the car sit for a day, and it's a cool (49F), rainy day, I measured the 12v battery at the battery with nothing but the dome lights on, 11.9v only. So it looks like it's time for a new battery. Not bad for seven years.