Hey guys, need some help. Today i was out with the car, weather was perfect so i decided to take my gimbal and drone out to get some footage of the car. Car was parked, headlights weren't on or anything. Attempted to start my car up to leave, and all of a sudden, car just clicks, dashboard just goes crazy and starts freaking out. Ended up not being able to start the car so i called Roadside assistance who came out pretty quick to jump the car, started up perfect but now with a check engine light and the "Trac Off" light is now on. Drove home, the car drove fine, no issues. Got home and pulled the code (P0121 Throttle/Pedal position sensor/switch A circuit Range/Performance) Never had any issues prior to this whatsoever, car is babied. This is super strange. Battery has to be good, it's been on a tender all winter and no recent issues starting it or any type of signal that would lead to believe the battery is bad or what cause issues. Anyone have this code before? Recommendations or insight? I did a search but didn't find anything F related. Car is currently in the garage back on the battery tender.

One thing i did notice as i was driving home was that when the car was parked and i would close the door, i would hear 2 or 3 beeps. Didn't think much of it but it just started maybe 15 minutes before i was getting ready to leave.

 

I have had the dash and lights go crazy on me when the battery was weak. It must be an old battery and getting weak. Despite being on battery tender, batteries tend to weaken. It was throwing weird errors like 'TVD malfunction' and the dash lights with headlights were flashing very quickly. It only happened when I tried to start the car, but never happened when I first turned on accessory mode to see if there was enough charge. It was back to normal once I jump started it. It was about 2 years ago. I replaced the battery with the lightweight AG battery last month. I would recommend checking the battery first.

 

Thanks Rolla, will probably end up getting a new battery soon.

 

Everyone should have one of these


You probably have a bad cell

Nothing likes low voltage

 

Another vote for old dying battery. I had one that would charge on the tender as well, but within a week it wouldn't start the car. At this point I just assume a car battery over 4 years old is running on borrowed time. Even had the one in my wife's Armada fail recently, and the truck is only 3 years old, had a bunch of odd electrical symptoms leading up giving up.

 

That's symptoms of a bad battery or alternator. I had a Craftsman trickle charger that was killing car batteries. Didn't realize it until it killed two of my cars batteries.

 

Thanks guys, looking around now. Was considering going with the Antigravity battery (saw your video btw rolla), or even an agm battery but ultimately i think I'm going to replace it with the oem Panasonic battery, main reason being the battery has lasted close to 7 years without problems. Cant argue with that.

 

You get restart technology/battery management and also 12 lbs lightweight as well (as you say in my posts). I have let it sit for 1.5 week and it starts crazy fast on the first try. Highly recommend the AG-H6-RS. Since I exported it out of US an with the currency conversion, it was a lot more expensive than it would be for you. I got the 30 Ah for $659 USD, but with duty, shipping, taxes, conversion, it ended up being nearly $1100 CAD for me. Still, I think it is totally worth it.

 

Follow up question. Today was the first day out with the car since I installed the new battery. All is good, however I’m noticing my downshifts in manual mode from 5th to 4th and 4th to 3rd are jerky and not nearly as smooth as they were before, not driving aggressively. Is there a relearn process? Was the transmission shift behavior reset after the battery was removed?

 

When I replaced my battery with the AG-H6-RS Antigravity battery, I did not notice any difference as far as downshifts go. More or less, feels the same. Are you getting the rev-matching on downshifts? Was the engine properly warmed up?

 

Definitely warmed up (40 min of driving), it is rev matching. There’s a possibility this may just be in my head.

 

How long was the battery dead, or left out of the car? On the cars I've worked on, having the battery disconnected entirely for more than a couple minutes drains the system of power, and makes some logic and learning things reset. I had an older car (2000's) that had AGGRESSIVE shift logic, whoever drove that thing before was an absolute maniac. After disconnecting the battery for a day (needed a new one) the shift logic was smoother, less aggressive.

 

It was disconnected for about a day (the battery came in the following afternoon)

 

I recently had my battery replaced at the lexus dealer, I also noticed the transmission doing weird stuff once I got the car back. One time when I floored it the car went from 7rh gear to second then back to 6th and it continued to gear hunt for like 6/7 seconds when my foot was flat to the floor in sport mode. I have literally no idea why it did that. A quick backroad blast in sport + and manual fixed that for me, after that I haven't noticed any more weird shifting.