Multi Information Display not Working

The battery is 5 years old and driving a total of 25000 miles didn't keep it fully charged. The BatteryMinder will help prolong the life of the battery but it is due for replacement.

 

Date: May 2015

I have a 2010 Toyota prius and after approx. five and half years and 52000 miles on it, the auxiliary battery failed. I am posting this info in the case this helps someone else facing similar issues I did.

Background Story (read if you have the time; if not, skip ahead to Symptoms of a dead aux. battery) :
I was a long distance road trip when I stopped at a rest area. After a brief stop, when I tried starting the car it wouldn't start. Pressing the start button with brakes depressed did not start the vehicle. Tried multiple times..the power/start button would go to "orange light" status but the engine wouldn't start. I tried to either turn off or unplug all power drains such as removing the gps, phone charger and also toggled the a/c button to ensure that it wouldn't kick in...switched everything off, waited for a couple of minutes and tried the start procedure one more time and the car turned on. With a sign of relief, then drove away. Car and all other electronics ran fine. My next stop was at my hotel that evening. After I parked in a safe spot in the parking lot, I turned off and tried to turn the car back on again with no luck. I tried several times but wasn't lucky. Luckily, I was near an autozone auto parts store. so, walked a half mile to the store to get DC jump start battery kit. Hooked it to the front jump start locations. no dice. (turned out i didn't put the negative cable at the right spot; note that the negative cable hooks to a long bolt to the left of the engine; refer to the owners manual on where this is located; it's listed there). Next, I tried jump starting using the rear battery location. Since my aux battery died, I couldn't open the trunk using the button. I then had to enter through the rear door of the prius, remove the storage area compartment cover and the plastic hard storage tray, remove the plastic tab covering the manual latch and then pull it to open the trunk (they made it so damn difficult to open the trunk manually!!). Once I hooked up the jump starter battery, I started the car and it started fine. however, the Multi information display (MID) wouldn't show/display. I saw the left display which shows the speedometer, mpg etc work but not the MID (which has info on the hybrid system). I turned off the car and started it again. same thing..MID wouldn't work. I left the car running for a little bit to see if the aux battery would charge up. After a few minutes, I saw the check engine light up!! I was worried if the engine was damaged somehow. turned off the car. tried starting the car again but it wouldn't. The aux battery didn't charge enough. the reading lights were dim when switched on indicating the charge was still low. I went to my hotel room at this point to rest and to deal with this in the morning. I looked up the nearest dealers and found one within 2 miles.

I called the nearest toyota dealer the next morning (luckily, they were within two miles and were ready to take my car in without prior appointment to replace the aux. battery). I jump started my car and went to the dealer directly. explained the problem, handed them the keys. They said it would be $275 total ($200 parts&tax + labor $75 for 1 hour) and take an hour to replace while I wait. I readily accepted, waited the hour. picked up my car and checked on the MID and it was working fine. No check engine light. All systems seemed to working normally. I was extremely relieved and went on my merry way. No issues thereafter.

Symptoms of a dead aux. battery:
+ Car may not start. The power would go to 'orange light' status but not turn green or hear the engine start.
+ the reading light would be dim when switched on
+ The MID may not show/display.
+ depending on sequnce of events and under some circumstances, the check engine light might come on.
I read somewhere that aux. battery is only used to turn on the internal computer which then controls all the systems in the car including the engine start/stop. So, if the computer doesn't come on properly, it could show false indicators.

Root Cause:
The root cause here was the aux. battery was dead and end of life. So, wouldn't charge/retain a charge.

Resolution:
Replaced the aux. battery.
Total cost was $275 ($200 parts& tax for 12v aux. battery and 1 hour labar charge@$75). I inquired the cost of 3rd party Optima battery at Autozone and it was quoted to be $229 excluding tax.

Note to self:
Better to get aux. battery checked and replaced in advance of End of life and before it goes dead on you on a long distance road trip.

 

I had the exact same issue today. Jumpstarted my car’s battery and was able to drive the car, but the multi information display was not on. After driving around for an hour, turned car off, went inside to read this forum, Went outside, whispered a silent Hail Mary, turned car on, and the MID came back to life. Happy 2019!