Anyone have their key fobs stop communicating with the PCM after their battery died?

[chriswinters18]

Question in title, but has anyone had their fobs stop working after their battery died? Dealer killed the battery, and is clueless how to fix the mess they created...

TLDR; truck went in for rear diff replacement, dealer sat on it for two weeks, battery died, they screwed something up swapping the battery and basically bricked the PCM and now the truck won’t run.

Full story; my truck was popping a code for the rear axle locker, dealer determined the rear differential needs to be replaced, thankfully under warranty, and after ordering parts it went into the shop on May 8th to have the repairs done. Same day they fired a mechanic and had another one quit, leaving them with one mechanic certified to do this particular job. After getting the run around for two weeks because they were backed up they finally went to work on my truck on the 23rd at which time the battery had died and could not be recharged. Not sure what caused the battery to drain to the point it couldn't be recharged, but they openly admitted it was possible they left a door ajar, or a light on...for two weeks in their parking lot. I ended up taking the battery myself to Autozone to get it replaced because the battery was only a year old and still under warranty.

I take the battery back the next morning, truck has power, but the key fob does not work. Came home, grabbed the other fob and that one doesn't work either. Not sure what they did, all they know is the fobs are not communicating with the PCM, and as of 2pm Friday when I showed back up to complain they had been trouble shooting for 4 hours and were unsure of what to do. It was made clear that it was going to get fixed on their dime as it worked when I gave it to them.

Word of advice; if you live in Hawaii, don't take your vehicle to Windward Ram in Kaneohe...they'll **** your **** up and not know how to fix it.

Truck's a 2020 Rebel. 45k miles.

 

[kapinallinen2]

Question in title, but has anyone had their fobs stop working after their battery died? Dealer killed the battery, and is clueless how to fix the mess they created...

TLDR; truck went in for rear diff replacement, dealer sat on it for two weeks, battery died, they screwed something up swapping the battery and basically bricked the PCM and now the truck won’t run.

Full story; my truck was popping a code for the rear axle locker, dealer determined the rear differential needs to be replaced, thankfully under warranty, and after ordering parts it went into the shop on May 8th to have the repairs done. Same day they fired a mechanic and had another one quit, leaving them with one mechanic certified to do this particular job. After getting the run around for two weeks because they were backed up they finally went to work on my truck on the 23rd at which time the battery had died and could not be recharged. Not sure what caused the battery to drain to the point it couldn't be recharged, but they openly admitted it was possible they left a door ajar, or a light on...for two weeks in their parking lot. I ended up taking the battery myself to Autozone to get it replaced because the battery was only a year old and still under warranty.

I take the battery back the next morning, truck has power, but the key fob does not work. Came home, grabbed the other fob and that one doesn't work either. Not sure what they did, all they know is the fobs are not communicating with the PCM, and as of 2pm Friday when I showed back up to complain they had been trouble shooting for 4 hours and were unsure of what to do. It was made clear that it was going to get fixed on their dime as it worked when I gave it to them.

Word of advice; if you live in Hawaii, don't take your vehicle to Windward Ram in Kaneohe...they'll **** your **** up and not know how to fix it.

Truck's a 2020 Rebel. 45k miles.

That sure sounds like the RF hub has taken a dump. Any evidence of water intrusion in the back?

 

[HSKR R/T]

The fobs don't communicate with the PCM. There is an RF hub, and a body control module.

When. You say don't communicate, do you mean they just don't work to lock/unlock doors and push button doesn't work when you plug with your finger? Or the truck won't even start when you push the start button with the fob itself? May sound crazy, but try removing and reinstalling the battery in the dmfob itself. Mine has been kind of finicky lately where I am remote loaci/unlock doors, but get inside and it says fob not detected. I do have an aftermarket fob though to get tailgate release. Reseat the battery in the fob and it will work again for a few weeks.

 

[chriswinters18]

That sure sounds like the RF hub has taken a dump. Any evidence of water intrusion in the back?

Yea that could be it. My rear window is actually supposed to be getting replaced for the second time next week because it’s been leaking.

 

[chriswinters18]

The fobs don't communicate with the PCM. There is an RF hub, and a body control module.

When. You say don't communicate, do you mean they just don't work to lock/unlock doors and push button doesn't work when you plug with your finger? Or the truck won't even start when you push the start button with the fob itself? May sound crazy, but try removing and reinstalling the battery in the dmfob itself. Mine has been kind of finicky lately where I am remote loaci/unlock doors, but get inside and it says fob not detected. I do have an aftermarket fob though to get tailgate release. Reseat the battery in the fob and it will work again for a few weeks.

Gotcha. Yea I don’t know how it all works, thats just what the dealer told me on Friday. As for what it is or isn’t doing none of the buttons on the fob work, and they are unable to start the truck. Someone else just mentioned the rf hub dying possibly due to water intrusion which is very possible because we got a lot of rain last week while it was sitting over at the dealer, and I’ve been waiting on getting my rear window replaced because it leaks. I’ll hopefully find out more on Tuesday when the reopen.

 

[bigdodge]

Yea that could be it. My rear window is actually supposed to be getting replaced for the second time next week because it’s been leaking.

and this is your issue.

when dealer left it out for a few weeks the rf hub got wet

 

[rick619]

Not in my Ram, but had that happen with a 2011 Lexus. The battery was totally dead so the key FOB didn't work, even after I jump started it. After I drove it for a few hours, the key fob worked again.