key fobs stop working after replacing the battery in the car

[rbgnr111]

I tried to start the car today, and got clicking. The battery was about 5yrs old, so after a few failed attempts, I thought I'd just replace the battery.
After replacing the battery, things got worse. I hopped in the car to start it up to test the battery... nothing. hitting the start button won't even light up with off... acc ... nothing.
I thought to hit the unlock, lock, and trunk button on the remote... again nothing. I thought maybe the battery isn't charged enough to start the car.. so I attempted to jump it. still nothing.
the only things that will come on are interior lights (bright since replacing the battery), headlights, and that security light just blinks.
I tried my wife's key fob... still nothing... replaced the battery in my key fob with a new one.. nothing.
at this point it seems like replacing the battery in the car has bricked it!
at this point, only the physical key opens the door...and other than that, it's as if I have no key.

[Ilya]

Welcome to the forum.

What happens when you put the fob into the fob slot on the dash? You might just need a reprogram but this is very odd indeed.

[rbgnr111]

I tried both keys in the slot in the dash. I get nothing. only the car beeping that the key was left in if I have the door open.... it does that even if I put my other car's key in it though.

I also noticed, my nissan has a similar push button to start. When I go in the nissan, the "lock" around the start button lights up... the inifniti.. stays dark.

[Ilya]

Hmm...that is crazy. The amount of threads lately with issues such as this is staggering.

[Opuseva]

I replaced the battery in my M35x twice over the years, did not have this type of problem. Have you inspected the fuses to see if something blew?

[FlawleZ]

Are you 200% sure the car is all the way in park?

[rbgnr111]

Are you 200% sure the car is all the way in park?

I did look at the fuses in by the battery, all looked OK.

Are you 200% sure the car is all the way in park?

unless I'm missing something, yes it is in park. I had it in the garage originally, then to try to jump it pushed it out onto the driveway, so, I've gone from park, to neutral, then back to park again.

[Costee]

The only thing I can think of is the Intelligent Key unit, though why it should suddenly quit beats me. The car can't even be scanned since the ignition can't be turned to the On position. Yes, it is said never to throw parts at the car but you just might have to take this chance. Be sure to check the fuses once again. From my reading of the diagram, it seems the I-Key unit is controlled by a 10A fuse, #22 in the fuse box under the dash.
Another possibility is that the key memory got lost in that transition between battery change. In that case, you'd need to get the key programmed again. This process begins with steering lock release, which requires the ignition to be in the Off position. In your shoes, I'd proceed with this second option.

[whitewolfdog74]

I'm having the same exact issue right now.had my mechanic come look at it,and he thinks maybe the start button or water in the harness.somebody also said maybe the ground.getting 12 volts at 1 wire on the start button,and like 2 volts on the others.

[EdBwoy]

For giggles, have you guys tried to start the car with the gear in Neutral? Make sure your brake lights are coming on when you push the brake.
For the sake of it, try the whole start sequence while jumping the car.

[whitewolfdog74]

Cant shift into any gear

[EdBwoy]

Use the shift lock access hole at the top left of the shifter gate

[whitewolfdog74]

How does that work?

[whitewolfdog74]

Figured it out,still nothing