Truck won't unlock after remote start

[Jimmy07]

No, that’s the resistance that the hood latch presents to the BCM when it’s closed. When the BCM sees 1k ohm from that circuit, it knows the hood is closed. If it’s not the correct resistance, the BCM will cancel the remote start and display the reason why on the EVIC.
Just compared your BCM log, and everything is good there. Is there ANY type of aftermarket accessory installed that turns on with remote start- radar detector, dash cam, anything that has led lights in it, etc?
When the truck is running normally (not in remote start mode), does the fob lock/unlock the truck like normal?

 

[kristof]

Nothing aftermarket. I have two garage openers in it for home and shop garage. Also it works normally if remote start not activated. What is weird is sometimes it works fine but most of the time it doesn't ( when remote start active)

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[kristof]

Is it possible I screw up the wiring somehow? I called local dealer about the problem today and the lady on the phone said it's wiring problem and to bring car in for diagnose and it will cost $150

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[kristof]

Is it possible the noise cancelling system might cause this? Maybe it should be disabled when remote start is runnig? Jimmy you want me to bring my truck to you

 

[Jimmy07]

Is it possible I screw up the wiring somehow? I called local dealer about the problem today and the lady on the phone said it's wiring problem and to bring car in for diagnose and it will cost $150

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No, because remote start works.

Is it possible the noise cancelling system might cause this? Maybe it should be disabled when remote start is runnig? Jimmy you want me to bring my truck to you

Not that, either, because there are rams optioned with remote start and ANC.
I believe this could probably be a fob issue. I have to ask this, just to take the option off the table, but have you tried several different brand new batteries in your fob yet, even if you think the one in there currently is brand new?
When you bought the fob, did it appear to be used? Did they send it in Mopar packaging, or their own packaging bag?

 

[kristof]

Fob was inside a lock plastic bag with their sticker on it. I will try different battery and see

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[kristof]

Here is a photo of the bag it arrived in


I will try new batteries and see.

 

[kristof]

I tried new battery Duracell 2032 and still the same problem

 

[Nucknfutz]

I have a 2020 ram 3500 bighorn that I bought in September, mfg date is in July, came with factory remote start, and I also have this issue. Have tried new batteries, and both fobs. Unlocks like a champ, until the truck is started. Then i can stand right at the door of the truck, and sometimes it unlocks, and others not. I find pressing and holding the unlock button and waiting for it to unlock seems to work better than pressing it multiple times, but there is definately an issue here that ram needs to look at. I havent had time to make it to the dealer for them to have a look but mine would definately be a warranty thing, as the truck is bone stock.

 

[kristof]

It will be nice if you go and let me know what was the problem. I tried close to the door like jimmy suggested and still the same.

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[Nucknfutz]

It will be nice if you go and let me know what was the problem. I tried close to the door like jimmy suggested and still the same.

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There isn’t a dealer where I live, which means I have to take a day off work to get the dealership to look at it. So i will probably be waiting until my first service which may be a bit.

 

[kristof]

I just tried with the fob that came with my truck and it won't unlock it either after remote started. So it's not the fob but something in the truck.

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[Nucknfutz]

2020 3500 gas , remote start works fine. Problem is when you try to unlock the door to get in you have to repeatedly push the unlock button. I'm going to have the dealership look at it. Just wondered if any one else has this issue.

Did you get yours figured out?

 

[kristof]

Jimmy I'm pretty sure you are watching this thread. Is it possible that I have problems with mine because when dealer put the sales codes in they have to flash the whole system ? And it takes them over an hour to do it and to me it took few minutes with AlfaOBD. Maybe I have to flash the system (whatever that mean) and it will work fine then?

 

[Jimmy07]

Jimmy I'm pretty sure you are watching this thread. Is it possible that I have problems with mine because when dealer put the sales codes in they have to flash the whole system ? And it takes them over an hour to do it and to me it took few minutes with AlfaOBD. Maybe I have to flash the system (whatever that mean) and it will work fine then?

No, when the dealer “flashes” a sales code, the actual bits that get changed in the BCM are exactly the same, and take the same amount of time whether it’s the dealer’s tool doing it or AlfaOBD. It’s not possible for a setting change to be “partially done”, it’s either the bits changed, or they didn’t. The part that takes time at the dealer is verifying with FCA that your build sheet has been updated in the dealer connect system to show the remote start sales code as a “dealer installed option”.

 

[kristof]

No, when the dealer “flashes” a sales code, the actual bits that get changed in the BCM are exactly the same, and take the same amount of time whether it’s the dealer’s tool doing it or AlfaOBD. It’s not possible for a setting change to be “partially done”, it’s either the bits changed, or they didn’t. The part that takes time at the dealer is verifying with FCA that your build sheet has been updated in the dealer connect system to show the remote start sales code as a “dealer installed option”.

Got it. I'm just so frustrated with this thing not unlocking that I look at every option possible. If I unlock with emeregency key truck shuts off (how it suppose too). Right now I hesitate to use the remote start option at all. Too much headache just standing there and waiting for it to unlock. I tried the location in the back like you said and same results. I tried the original fob and still won't unlock. I know the software in my truck is little bit slow cause most of the time after I press a button next to my screen I have to wait like 4 second before it switch to whatever I chose. But i don't think this will be a problem.

 

[Jimmy07]

Got it. I'm just so frustrated with this thing not unlocking that I look at every option possible. If I unlock with emeregency key truck shuts off (how it suppose too). Right now I hesitate to use the remote start option at all. Too much headache just standing there and waiting for it to unlock. I tried the location in the back like you said and same results. I tried the original fob and still won't unlock. I know the software in my truck is little bit slow cause most of the time after I press a button next to my screen I have to wait like 4 second before it switch to whatever I chose. But i don't think this will be a problem.

I’m completely stumped at this point, too. I’m starting to see more of this same issue pop up on some other forums also- even factory equipped remote start situations.

 

[Nucknfutz]

So i did a bit more of my own testing yesterday and found that when remote start is active or even when the truck is left running and you get out and lock it to say run into a store, the fob is slow to respond in both locking and unlocking events. I am a Radio tech by trade, so I also tested the keyfobs, they seem to be in the 433-434Mhz range, and then also used an Anritsu Spectrum analyzer to see if there was any RFI (RF Interference) being generated while the truck was running. As far as I could see with olacing the unit in the cab, and walking around outside, there was none. I am going to try running the antenna for the analyzer along the wiring that goes to the rf hub and at the rf hub to see if it may be interference coming uo the wiring. At this point I am trying to figure out if the rf hub is properly processing the lock/unlock commands, and just not getting them to the bcm, or if the fob’s rf is somehow being distorted /interfered with causing the rf hub to ignore them. Does anyone know if you can see the live fob press activity info in Alfa OBD? Also. Where is the RF hub located in a 2020 Mega cab?

 

[kristof]

So i did a bit more of my own testing yesterday and found that when remote start is active or even when the truck is left running and you get out and lock it to say run into a store, the fob is slow to respond in both locking and unlocking events. I am a Radio tech by trade, so I also tested the keyfobs, they seem to be in the 433-434Mhz range, and then also used an Anritsu Spectrum analyzer to see if there was any RFI (RF Interference) being generated while the truck was running. As far as I could see with olacing the unit in the cab, and walking around outside, there was none. I am going to try running the antenna for the analyzer along the wiring that goes to the rf hub and at the rf hub to see if it may be interference coming uo the wiring. At this point I am trying to figure out if the rf hub is properly processing the lock/unlock commands, and just not getting them to the bcm, or if the fob’s rf is somehow being distorted /interfered with causing the rf hub to ignore them. Does anyone know if you can see the live fob press activity info in Alfa OBD? Also. Where is the RF hub located in a 2020 Mega cab?

Now that's some science stuff

 

[kristof]

Can sirius radio cause the issue? It looks like the issue only exists if the truck is on. Maybe I will get inside the truck remote start it and then try to unlock it with fob