How-To: Cell Comm Killer.

[Diboblo]

For those of us who value their privacy and prefer not to participate in forced UConnect OTA updates, I have developed a single that effectively blocks all cell comms, inbound and outbound.

NAV and Cell are separate systems and have separate antennae. Blocking cell comms does NOT interfere with NAV. There is also some confusion about Performance Pages. This mod does NOT disable PP. If you have them, you keep them.

In the first month, I experienced 1 bar, 1G bleed. After that, zero. I have had zero cell comms, for a couple of years. Zero issues. Several dealer visits. No problem. You will get a nag screen that you can ignore and it will go away, or you can simply press OK and it will disappear, for the duration of that key cycle.

Things you need:

5 min epoxy

FAKRA D connector (cell comm)

10k (10,000) ohm 7 watt resistor, wire wound

3" square of copper Faraday fabric

1/2" diameter weatherproof shrink tube. About 2" long.

Heat gun, or lighter (to shrink the tubing over the end product).

Lay everything out, end to end, so you get an idea of how this goes together.

Cut down 1 lead, of the resistor and solder it into the signal pin.

Insert the signal pin and resistor, into the connector and solder the other resistor lead to the connector shield.

No picture, but at this point, epoxy the center resistor lead I side the metal FAKRA housing, so it doesn't bend and short.

Once the epoxy is dry (about 15 min), fold your Faraday cloth into a triangle.

Wrap the resistor tightly and slip the shrink tubing over and heat. You will have a little bit beyond the end of the resistor. While hot, pinch this closed.

NOTE: You will have extra Faraday cloth, beyond the resistor. Fold that over, before installing the shrink tubing.

With the car OFF, remove the screen and radio module, behind it.

Unplug the FAKRA D connector (same color) and ugh in your dongle.

Re-assemble radio and screen.

Enjoy your privacy.

Bob

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[Diboblo]

@WIKI

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[Diboblo]

Yes, the resistor shown is not 10k. Just wanted to get this out there, for you guys.

Bob

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[Detroitboy]

Excuse my electronic ignorance, but I can solder well. So does this affect our cell phone ability in any way? I assume we would not be able to use the feature of just taking calls thru the screen and speaking without using our phones? Without this modification are our spoken conversations recorded or does this only affect texting?
Thanks for some education. I always love to learn new things about our cars.

 

[Diboblo]

Excuse my electronic ignorance, but I can solder well. So does this affect our cell phone ability in any way? I assume we would not be able to use the feature of just taking calls thru the screen and speaking without using our phones? Without this modification are our spoken conversations recorded or does this only affect texting?
Thanks for some education. I always love to learn new things about our cars.

I am familiar with the recent supreme court ruling that allows automakers to skim your texts and phone usage. Real bummer, for our privacy and I get your concern.

Your physical cell phone performance is not compromised, by this mod. You can use it, stand alone, or via onboard bluetooth.

Your vehicle is equipped with a 3G cell, which both transmits and receives data. In conjunction with the cell, the onboard network skims your cell data and sends it to Stellantis. They, in turn, sell it to the highest bidder, or anyone with a credit card.

Because the cell is disabled, there is nowhere for any skimmed data to go. Like a cellular vasectomy. So, who cares if the car skims data.

You can still receive and send data, via the onboard network and a paired phone. Bluetooth does not pass cellcomms via the onboard cell. It's like a pair of bt headphones.

Neither does this mod compromise texts. If you have allowed the network access to your contacts, I recommend resetting the radio and your personal settings... after applying this mod.

You still have full nav access and sirius (though I just built a sirius blocker, for my car).

I've had this mod, for quite sometime and have had zero issues using my phone as I see fit.

Hope this helps.

Bob

 

[Deano]

FWIW, Robert made one of these dongles for me. After a year, I've not had any issues and no U-connect updates.

 

[Detroitboy]

Thank you Bob

 

[HotWheels22]

Bob,

Apologies for the longer post, but my goal is to provide some info to folks who may be searching for it, as well as to ask a couple of questions. I haven't found all of this info in one place otherwise. Looks like I'll have to post this in a couple of parts due to length.

As you seem to be one of the few folks I can find on the Internet interested in really digging into the details of the telemetry side of Dodge products, really appreciate this design/writeup. As I'm sure you're well aware, there's a lot of poor information out there on the telemetry systems in general, but not much that's useful when it comes to countering/removing it without collateral damage (of services/features).

Hope I can get your thoughts on a couple of questions in the same vein. On the 2023 Challengers with UConnect 8.4 with Nav, the antenna arrangement is a little bit puzzling. I'm intending to construct your above project, but have done some testing on the head unit and antenna configuration in the mean time.

The goal is to get the 4G radio disabled entirely, without losing satellite comms for radio reception and GPS Satellites. The preference would be electrically disabling the 4G radio/air card, but I suspect your project arose from learning that means the loss of satcomm also.

There are good guides available for the disconnection (total removal is not necessary) of the Sierra AR7552 card from inside the head unit, and I've confirmed that disconnecting the card is effective in removing ALL 4G comms from the vehicle. The obvious plus to an electrical disconnect is there's no chance of surprises, leaks, or re-enablement without your knowledge. Downside is this kills GPS satcomm (but NOT SXM radio) in the process.

From everything I can discern, the Sierra AR7552 has the GNSS (GPS and GLONASS) capablilities embedded in it, so the actual hardware to do GPS location is part of that daughter card itself. Remove the Sierra card completely, and you remove the embedded GPS capabilities it brings. (E.g., "This paper atlas comes with a creepy dude who rides in your trunk and watches you whereever you go. Cool? Cool.")

Frank Smith's post on the Jeep 4xe forum on how to remove the cellular modem suggests that the nav still works, however, that wasn't the case for me. What I've seen is that nav doesn't instantly lose track of where you are when the satellite links are removed. It uses a combination of the magnetic compass, last known location, and vehicle velocity to continue to estimate the location, and for a short while (couple miles) it seems to track OK, but it doesn't take long to drift heavily, ending up miles off of your actual location. A quick initial test, however, makes it seem like the nav still works, even though satcomm is gone.

...

 

[HotWheels22]

...

The head unit's rear layout for the male FAKRA connectors is as follows (borrowed from another forum post but the header setup is the same:


For my purposes here, I'll use the color names from Left to Right: Purple, White, Blue, Pink, (Red: not used; Gray is the USB header)


I've found a couple of conflicting interpretations of exactly what these connectors map to. In my own testing (again, 2023 Challenger UConnect 8.4 with Nav):
- Blue is the satcomm connection for both GPS satellites and SXM radio. If this antenna is disconnected, all satellites drop. This can be verified for Nav by going to Nav > information > current position > show GPS Info. This will display the current satellite array, how many are locked, and signal strength for all. If the blue plug is removed, this drops to 0 over about a 1-2 minute period. Likewise, satellite radio is rendered inoperable, no signal. My assumption is that this leads to the on-roof shark fin antenna. Lastly, satcomm was unaffected by pink/purple connections either way.
- White is AM/FM radio.

Here's where it gets a bit more interesting:

- Purple's lead is a long cable that goes into the wiring pack and out of sight, endpoint unknown. Some forums/sites suggest this is 4G, others satellite radio, and others GPS.
- Pink's lead is a short ~15" cable that leads to the in-dash black shark fin antenna, mounted just behind the head unit. Different sites assume different uses for this - some say GPS, some say 4G/cellular.

In testing:
- Removing/reconnecting blue had zero affect on 4G signal strength, so I can assume the 4G radio does not use this header at all.
- Removing pink/purple together dropped the 4G strength from 5 bars to 3, but there's still a solid 3-bar connection and (dis)services such as weather alerts still operate.
- Removing pink alone had no effect on 4G strength, remained at 5 bars.
- Removing purple alone DID lower the 4G signal (to 4-5 bars, back and forth), but NOT as low as removing purple and pink together.


The data seems to indicate that the purple connector may go to the primary 4G antenna, and that the pink connector (to the in-dash shark fin) may be the internal 4G/WiFi antenna designed to transmit/receive from devices inside the vehicle.
The data also seems to indicate that the 4G card is able to utilize either the pink OR purple antenna leads for external 4G data usage, but that the pink (dash shark fin) is less effective than the purple primary lead.

Lastly, given that the vehicle still has 3 out of 5 bars of 4G service with all the leads disconnected, this tells me there's an on-card antenna (not surprising) that is used by default when there's no signal (perhaps specifically no resistance) detected on the external antenna lead. This aligns with the integration spec for the Sierra card. "The RX2 antenna diagnostic feature allows the AirPrime AR75520 to determine if the RX2 antenna connected to the module is: open, shorted or normal. The antenna connected to this interface needs to have a DC resistance to ground of 10 kΩ± 1k embedded inside", suggesting that if there is no antenna, it defaults to the internal antenna.


I expect that the above knowledge of an on-card integrated antenna is exactly what gave rise to your design - as unplugging the antennas doesn't stop the signal.
It looks from your post like you're using a different head unit that may not have an internal WiFi hotspot antenna (pink equivalent).

Questions:
- Does it make sense that the in-dash shark fin (pink) is the internal wifi antenna, and if so, that the 4G card could utilize it for external 4G transmission as an alternate to the primary (purple) antenna lead?
- Any reason to craft a second cellcomm killer for the pink FAKRA connector as well as one for the purple connector, or should the resistance detected on the primary circuit mean it doesn't try to broadcast on a secondary antenna?

Thanks again for the great info for the project, look forward to testing it and seeing if it solves the telemetry concerns.

 

[Diboblo]

Bob,

Apologies for the longer post, but my goal is to provide some info to folks who may be searching for it, as well as to ask a couple of questions. I haven't found all of this info in one place otherwise. Looks like I'll have to post this in a couple of parts due to length.

As you seem to be one of the few folks I can find on the Internet interested in really digging into the details of the telemetry side of Dodge products, really appreciate this design/writeup. As I'm sure you're well aware, there's a lot of poor information out there on the telemetry systems in general, but not much that's useful when it comes to countering/removing it without collateral damage (of services/features).

Hope I can get your thoughts on a couple of questions in the same vein. On the 2023 Challengers with UConnect 8.4 with Nav, the antenna arrangement is a little bit puzzling. I'm intending to construct your above project, but have done some testing on the head unit and antenna configuration in the mean time.

The goal is to get the 4G radio disabled entirely, without losing satellite comms for radio reception and GPS Satellites. The preference would be electrically disabling the 4G radio/air card, but I suspect your project arose from learning that means the loss of satcomm also.

There are good guides available for the disconnection (total removal is not necessary) of the Sierra AR7552 card from inside the head unit, and I've confirmed that disconnecting the card is effective in removing ALL 4G comms from the vehicle. The obvious plus to an electrical disconnect is there's no chance of surprises, leaks, or re-enablement without your knowledge. Downside is this kills GPS satcomm (but NOT SXM radio) in the process.

From everything I can discern, the Sierra AR7552 has the GNSS (GPS and GLONASS) capablilities embedded in it, so the actual hardware to do GPS location is part of that daughter card itself. Remove the Sierra card completely, and you remove the embedded GPS capabilities it brings. (E.g., "This paper atlas comes with a creepy dude who rides in your trunk and watches you whereever you go. Cool? Cool.")

Frank Smith's post on the Jeep 4xe forum on how to remove the cellular modem suggests that the nav still works, however, that wasn't the case for me. What I've seen is that nav doesn't instantly lose track of where you are when the satellite links are removed. It uses a combination of the magnetic compass, last known location, and vehicle velocity to continue to estimate the location, and for a short while (couple miles) it seems to track OK, but it doesn't take long to drift heavily, ending up miles off of your actual location. A quick initial test, however, makes it seem like the nav still works, even though satcomm is gone.

...

As I've stated, before. Cellcomms and satcomms are separate entities, with a caveat. It appears satcomms are parasitic to cellcomms, insofar as transmitting data.

If you disable cellcomms, with my dongle, you may also disable satcomms upstream transmissions (which sounds like your case). This is how Guardian "sees" your vehicle state... by pinging it. It is also how big brother can send you emails regarding engine state, etc. "They" can see your vehicle..

My vehicle didn't have these issues (MY15).

In total transparency, I NEVER use my satnav. Never. So, this issue isn't an issue, for me. I get where you're going. I did the research and built these lockouts, for total privacy. Are there offsets? Yes. Are there options? Yes.

I wanted total security, from Sirius and Stellantis. My car is off those grids. If I need nav, I use a Garmin Overlander. This is a direct satellite communicator. No cell needed. No blackouts. IMNSHO if you have a standalone nav and a phone, the cars systems are redundant.

Everyone needs to consider the degree of exposure they are comfortable with and go from there. This is a good thread, for discussion. Let's keep up the discussion.

 

[Lilschmied]

The wiring connector repair list on the mopar site does show 2 cell connections on a '23 challenger radio : (C11 - 4g) and (C7-cellular) I would suspect you need to terminate both to actually block the signal.

The bars on the display are likely signal quality rather than signal strength. So by disconnecting both antennas you see poor signal quality which makes sense since you have an unterminated transmission line and likely lots of rf noise/reflections. If you lived 20 miles from a tower that might be enough. However, for those of us that have so many towers they try to disguise them as trees, terminating the circuit(s) as shown here dissipates the energy in the circuit lowering the signal level enough that 2 way communication no longer works. Some signal may still be leaking in, but terminating the antenna ports and the additional Faraday cage prevents rf getting out to make the handshake.

 

[Diboblo]

The wiring connector repair list on the mopar site does show 2 cell connections on a '23 challenger radio : (C11 - 4g) and (C7-cellular) I would suspect you need to terminate both to actually block the signal.

The bars on the display are likely signal quality rather than signal strength. So by disconnecting both antennas you see poor signal quality which makes sense since you have an unterminated transmission line and likely lots of rf noise/reflections. If you lived 20 miles from a tower that might be enough. However, for those of us that have so many towers they try to disguise them as trees, terminating the circuit(s) as shown here dissipates the energy in the circuit lowering the signal level enough that 2 way communication no longer works. Some signal may still be leaking in, but terminating the antenna ports and the additional Faraday cage prevents rf getting out to make the handshake.

Yeah. My cell blocker includes a faraday wrap. Zero penetration, for years. LOL

 

[HotWheels22]

The wiring connector repair list on the mopar site does show 2 cell connections on a '23 challenger radio : (C11 - 4g) and (C7-cellular) I would suspect you need to terminate both to actually block the signal.

...

This seems possible to me too. I think my approach is going to be build one cell blocker, put it on what I gauge to be the primary antenna header, and then evaluate if there's signal. If needed, build a second and stuff the secondary antenna as well.

 

[Diboblo]

This seems possible to me too. I think my approach is going to be build one cell blocker, put it on what I gauge to be the primary antenna header, and then evaluate if there's signal. If needed, build a second and stuff the secondary antenna as well.

When you pull the radio, please post a photo of the back of it, where the connectors are. For future reference.

 

[HotWheels22]

As I've stated, before. Cellcomms and satcomms are separate entities, with a caveat. It appears satcomms are parasitic to cellcomms, insofar as transmitting data.

If you disable cellcomms, with my dongle, you may also disable satcomms upstream transmissions (which sounds like your case). This is how Guardian "sees" your vehicle state... by pinging it. It is also how big brother can send you emails regarding engine state, etc. "They" can see your vehicle..

My vehicle didn't have these issues (MY15).

In total transparency, I NEVER use my satnav. Never. So, this issue isn't an issue, for me. I get where you're going. I did the research and built these lockouts, for total privacy. Are there offsets? Yes. Are there options? Yes.

I wanted total security, from Sirius and Stellantis. My car is off those grids. If I need nav, I use a Garmin Overlander. This is a direct satellite communicator. No cell needed. No blackouts. IMNSHO if you have a standalone nav and a phone, the cars systems are redundant.

Everyone needs to consider the degree of exposure they are comfortable with and go from there. This is a good thread, for discussion. Let's keep up the discussion.

"Parasitic" is a great way to describe the way I understand the system (putting together different aspects from this thread and others). Satcomm on these systems seems to just be downstream. But as you say, the upstream is handled via cellular. Guardian itself states that if you're out of range of cellular service entirely, SOS and other emergency elements may/will not function. My understanding of the interaction is satellite is used to pinpoint location, and the GPS software hands that data off via cellular (regular pings of course, not just in emergencies) so the vehicle is always tracked. Even with LOS for cellular, a last known location would have already been transmitted.

Guardian has already been confirmed as disabled by the provider. Obviously this assumes they honor their own ToS, and without independent validation of some sort, it's not provable they do. That said, it's an accepted risk (as you say, personal decision, always).

Your usecase makes sense given what you want to achieve. There's a single-screen convenience offered by the integrated system, and in (some) previous versions of UConnect, there was no cellular connection anyway, so it was pure satellite just as a Garmin is.

To your point, your dongle should (and I hope will) disable satcomm upstream transmissions via cellular. That should not affect nav directly in any way that I'm aware of.

The thing that remains to be seen is whether it will take 1 cell-blocker dongle or 2 to take the xmit capability of the Sierra card offline.

 

[HotWheels22]

When you pull the radio, please post a photo of the back of it, where the connectors are. For future reference.

This matches the photo in my second post above, with the one difference that there's a header between red and pink FAKRA connectors on the other one, and there's not on this one.

 

[GNBRETT]

Why would I NOT want updates to my Uconnect? Im confused...... Its sux bad enough the way it is why would I not want updates to make to possibly function like normal?

 

[Diboblo]

Why would I NOT want updates to my Uconnect? Im confused...... Its sux bad enough the way it is why would I not want updates to make to possibly function like normal?

This is not a sale thread.

No one is here to convince anyone to make any changes, to their vehicle.

Through research, if you are inclined to block comms, this is a means to do so.

Updates are easy enough. They have always offered updates via usb. If one is so inclined, that is the way... if your comms are blocked.

There are a plethora of reasons people have to block comms; OTA updates is just one.

Thanks for your comment. I know people will have questions about this mod. Like I've said before, we should determine what level of security we want, if any... then go from there.

 

[Linda's Hell Cat]

"OTA updates is just one." @Diboblo can't they be done without permission too?

Linda

 

[Diboblo]

"OTA updates is just one." @Diboblo can't they be done without permission too?

Linda

Yes.

Essentially all over the air updates are done, without your permission. Once the packet is downloaded (usually over several days), it is resident and in some cases, will not let you use your infotainment screen, until you accept their terms and update. One cannot refuse the resident update. Nor, can one refuse to have it downloaded. Hence the desire to block access to the vehicle network.

I ran into this, with 18-45-01. It fucked my nav and I had to wait for them to send me a usb. THEN, it fucked my performance pages and leaves stupid yellow warning triangles, when I select a pre-set custom mode. Just another example of their many update failures.