2017 Grand Cherokee Summit frequently displays the "Key Fob Not Detected" message when I push the engine start button. Sometimes I can get the car to start with the push button by holding the key fob close to the instrument cluster, but other times even that does not work. If holding the key fob up to the instrument cluster doesn't work with the push button, I can sometimes get the vehicle started by using the end of the fob on the start button (as recommended elsewhere on this site) but recently even that does not always work; in those instances I usually end up locking and unlocking the doors from inside the vehicle and then the start button seems to work.

I have replaced the battery in the fobs multiple times with no improvement. Both of the fobs that came with the vehicle exhibit the same behavior relative to the start button; both fobs also always lock and unlock the vehicle from a very long distance so at least one of the 'remote' functions of the fob and the vehicle are working just fine.

I installed a new main battery in the vehicle about a year ago and it seems that this behavior has started to show up since then.

Any ideas what the problem might be, and is there any possible relationship between the battery replacement and this problem showing up?

Does anyone know if the vehicle remote lock/unlock receiver is different hardware than the engine start button receiver?

For some reason it seems like the fob eats the battery. I need to replace mine every 3-4 weeks as the range decreases pretty quick at about that point. Not all 2032s are created equal and I buy them cheap and in bulk, so theres that to consider,

 

For some reason it seems like the fob eats the battery. I need to replace mine every 3-4 weeks as the range decreases pretty quick at about that point. Not all 2032s are created equal and I buy them cheap and in bulk, so theres that to consider,

Apparently not. I'm still using the original battery in the fob for my 2018 GC that I bought 4.5 years ago. The remote start still works from over 150 ft away.

 

Does remote start via your FOB start the engine reliably?

The receiver in the ignition switch reads the RFID chip on the FOB, the FOB does not need any power, nor battery for that matter.

The remoted functions and passive entry are via a different RADIO and is handled by a body module, the same module as the ignition but are independent functions. Does your passive entry work reliably (locks/unlocks via touching the door handles) ?

I would try reseting the Jeep by disconnecting the battery(s) negative terminal for 5 minutes.

If that doesn't improve function, I would check the module under the passenger side dash behind the glove box for water damage from a leaking windshield.

Otherwise I think you will need a full function scanner to read body module codes and troubleshoot. ... I would think FOB batteries would not affect the reliability of starting the Jeep via pushing the start button with the business end of the FOB.

 

Wrapping up this issue: after waiting for 4 months for a new "RF Hub" and paying $500 to have it installed at the dealership, problem repeated the next day. I contacted the dealership and they asked to have the car back to check the antennas. Car was in for six hours for that but the dealership never checked the antennas, just tried to get the problem to happen which they knew was unlikely as it was very intermittent. I was obviously upset with the dealership service writer and asked if they could contact Jeep to try to get some advice as to what to do next - was told that Jeep will not help them.

The vehicle is so unreliable that my wife won't drive it and I hesitate to lend it to anyone who needs the towing capacity. After at least four trips to the dealership and $600-700 spent with no improvement and no assurance that there was any clear path to solving the issue, it was time to say goodbye to the Grand Cherokee. Thought briefly about another new Summit but the price they are asking for those is off the charts. Example of how Jeep is overcharging is in the delivery charge: Jeep charges $600 more in delivery charges than Mercedes.

Good luck to all and thanks for providing input on this and a few other issues during my time with the Summit.

 

Wrapping up this issue: after waiting for 4 months for a new "RF Hub" and paying $500 to have it installed at the dealership, problem repeated the next day. I contacted the dealership and they asked to have the car back to check the antennas. Car was in for six hours for that but the dealership never checked the antennas, just tried to get the problem to happen which they knew was unlikely as it was very intermittent. I was obviously upset with the dealership service writer and asked if they could contact Jeep to try to get some advice as to what to do next - was told that Jeep will not help them.

The vehicle is so unreliable that my wife won't drive it and I hesitate to lend it to anyone who needs the towing capacity. After at least four trips to the dealership and $600-700 spent with no improvement and no assurance that there was any clear path to solving the issue, it was time to say goodbye to the Grand Cherokee. Thought briefly about another new Summit but the price they are asking for those is off the charts. Example of how Jeep is overcharging is in the delivery charge: Jeep charges $600 more in delivery charges than Mercedes.

Good luck to all and thanks for providing input on this and a few other issues during my time with the Summit.

 

Hope you have many miles with smiles with your new adventure. Sounds like the dealer was giving you BS. Not that you should need to but did you try another dealer, or contact Jeep customer care directly?

A bad connection at the tailgate antenna is well known to cause these kinds of things, but pressing the start button with the business end of the FOB should always start the Jeep, unless something else is going on.

 

Did your make sure the battery in the key fob is in correctly? The positive side should be down and properly seated.

 

I totally understand what a headache some of us Jelep owners are going through.
I have been screwed a few times by 2 different dealerships, one in Queens NY and the other in long Island, so I really don't want to go back with this.

I have the same problem with my 2017 Jeep Grand Cherokee. My problem started in June of 2024. I have changed the batteries, and that didn't help.
I did a volt test on the new batteries, and some had 3.08 volts. For some reason, the remotes like a new battery with 3.32 volts.
For some reason I cam start the car from 10 to 15 car lengths away but when I get inside of the vehicle, it states key fob not detected. Sometimes you can hit the unlock button on the fob and the vehicle will start. Other times you have to hit the start button with the fob to start.
Then you have the bad days, where you can remote start the vehicle but can't move the vehicle because she doesn't detect the fob at all no matter what you do.

I started keeping brand new batteries in the vehicle but that didn't help.

The second fob works so I am guessing that the main fob I used for years is malfunctioning.

Im thinking about buying another fob just to have as a backup

 

The remote start and the push to start button uses two different radios and two different antennas. So it is not unexpected that one will work and not the other.

When you press the start button with the business end of the FOB, a RFID reader within the ignition switch is used that does not require a FOB battery. If the Jeep is not detecting one FOB but detecting the other, I'd suspect the FOB has an issue not related to batteries.

 

Been having this problem lately. Usually when leaving home from work.

I will hit the remote start just so I can get home.

Yesterday at home the radio touch screen was just BLANK. Like it was OFF. After a minute it came up. The vehicle started. It was like it had a brain fart or a total reset. I could not get the rear defogger to shut off. WTH.

Just trying to figure this out before it leaves me stranded. I replaced the FOB battery a few weeks ago and the main batteries a year ago...

Checked the main battery terminals for looseness, all OK. Fob battery at 3.02 VDC. 12.45 VDC under the hood. Just checked these things... 🤷‍♂️

Look at all the modules!!

https://store.mopar.com/v-2016-jeep-grand-cherokee--75th-anniversary--3-6l-v6-flex/electrical--keys-modules-and-engine-controllers

 

Weird things is usually a haunted vehicle or the TIPM,. Sometimes a bad connection in one of those TIPM or PCM connectors. You may want to check out the haunted vehicle thread in the maintenance sticky.

In early models, there is a fuse J12 for the rear window heater when you want to disconnect it. The removable relay may be worn to the point that the contacts stick closed. There are also dash buttons that can wear.

But just about everything is controlled by the TIPM circuit board which can go bad over time.

 

Worked fine on my commute yesterday... 🤷‍♂️