Hi all, I just changed my key battery on my 2012 Prius and now the car won’t start with the key fob. YouTube said to hold the fob over the ‘push start’ and hold the brake, but it still won’t turn on. When I try and start the car as normal several warning lights are on with the normal lights -check engine -car with lock symbol -steering wheel with exclamation point **And the car makes a noise like it’s trying to catch and start but won’t.
The key fob might be a red-herring. To clarify, you use the key fob and get a GREEN on the start button? Could you please clarify the sound you are getting? Is it just a click (solenoid) or is the engine actually turning over but not starting? What is the status of the headlights during your attempt to start? Do they dim dramatically or go off entirely (battery).
Yes, the push start button will turn green when fob is over it but it won’t start it like the YouTube video suggested. I didn’t turn my headlights on, so I didn’t notice anything there yet. The sound is more of something try to catch. Maybe the motor turning. Couldn’t quite gage what it sounded like. I was thinking my 12v battery might be dead but am not sure yet
WHY did you change that battery ? Does it act differently when using your "spare" key FOB ? Sounds maybe like the problem wasn't really the FOB battery to start with. IF......you don't have a second spare FOB, you REALLY need to get one after you solve this problem. If your ONLY FOB gets lost or fails, it can be VERY expensive to fix that.
I originally had a dead fob battery. Now, it won’t start my Prius. No, no, it’s none of that. I have both key fobs and I haven’t replaced my 12v battery yet. My key fob battery died and after I replaced it, it wouldn’t start my car. I’m not sure what the problem is.
When my 12v was getting weak it kept giving me a "key not detected" message. Eventually it gave me a "auxillary battery low" warning. Could be your 12v is bad and it was giving you the warning making you think the fob key needed replacing. And all those trouble lights you mentioned are normal when you first turn on the car...
Oh, okay. Maybe I should get my 12v checked. The hazard lights stayed on, they didn’t turn off. Okay, it turns out it was the battery all along. Is changed and the car is back to normal. Thanks to everyone for your help!
Note that this is supposed to work with a completely dead FOB battery. So if this doesn't work (which everyone should practice once) you have a dead/low 12v battery or a more severe problem. Mike
