[Capricio]

After the seeing the concerns across at least 4 different threads about the recent rash of thefts of our beloved cars, I thought I'd start documenting the efforts of myself and my friend "J". J is a former professional audio/alarm installer who now works in IT, and I know professionally. He deserves the credit for this design and honestly did most of the research, editing, and documentation. He's not a member of this forum but I'm grateful for his help and I couldn't have done this without him.

We wanted to create a DIY implementation with some inexpensive parts, and provide detailed instructions that would allow a non-expert competent DIY person to follow. I think the total cost is under $100 assuming you have all the required tools. Everything is available for purchase on Amazon.

We placed 10k resistors between the Data1+ and Data1- dummy OBD pins. likewise the Data2 pins. This also an optional step to the implementation.
Thanks to Keep_hope_alive for this suggestion:

"The intent of the 10k ohm resistors, one from each data pin to associated signal ground, is to make the reader think there is a circuit but it won't understand why it doesn't read any data. It prevents errors from an open circuit. The 10k ohm size ensures that nothing is damaged and is close to the input resistance of the actual circuit."

So, we fake the ECU circuit with the 10k resistors. The cloning tool sends out 2-5VDC, and establishes OSI layer 2 connectivity (with itself) for a serial connection. L3 and above obviously will not work, but this serves as another layer of obfuscation to confuse a thief into believing the dummy port may be operational.

Additionally, I recommend putting a cheap (3D printed) OBD2 lock on your dummy cable. It will help convince/distract a thief that the port was worth protecting, slow them down, and any damage done removing the lock will be on the dummy port.

With the relay boards in "MODE 12", once triggered, they will keep a persistent output condition even when the offending OBD reader is removed, until either the timers elapse or the reset button is pressed. If everything in this system were ripped out, the car will not start. With everything in place, the car will start and remote start should still work. The relay boards have a lower power mode with nothing displayed and have a non-volitile memory if they lose continuous power, they should resume operating how they were last configured.

Here's a demo video of the final operating model on a bench:

We included two independent timer relays to control the starter lockout and the siren duration. You could do the project with a single timer relay board, with the same duration applied to the siren and the starter lockout.

Tools:

Wire stripper,
crimper,
multimeter,
12VDC source (old battery for bench testing),
soldering iron,
butane lighter,
pin removal tool (optional),
Ferrule crimper (optional).

Materials: Multiple colors of wire, at least red and black. 16-18 AWG is more than adequate.

Ferrule crimps (optional).

Solder melt butt connectors.

Wago clips (optional),

10k Ohm resistors,

5A blade fuses


shrink tubing.

Parts:

2X Timer boards

Posi-Tap connectors

OBD2 Pigtail

Momentary Reset Switch

5 Pin Relay Harness (optional, only need one)

Mini Piezo Siren

Fused distro block

5 pin relay 5pin single pole double throw Waterproof to handle any kind of moisture that might or might not hit it 40amp capable


That's all I can provide for now, more videos and drawings will follow. Feel free to ask questions and hopefully someone else will benefit from this.

[h018871]

Thank you for this

[Capricio]

Originally Posted by h018871

Thank you for this

We finally got the entire system installed yesterday. It works perfectly and we should have a short video soon. Had a funky issue with a ground loop using the big relay grounded through the fuse block bus, so we gave it it's own ground. We also used the opportunity to install a footwell lighting kit. We'll try to get the schematic, videos of the finished install, placement of components, and programming the relay boards.

We fused everything for 5A. We took 12V constant positapped from the real OBD and positapped ground(s) from wires going to lug near the dead petal behind some carpeting. You could be more ambitious and find a better constant power from the power plug in the center console or the big wire in the BCM. Most of the parts fit in the cavity accessible by removing the side panel from the dash, where you can see a color legend for the BCM plugs, below the vent. We ran the reset button to the glovebox and taped it the top so it's only visible by getting your head pretty low, but can easily be found through tactile/feeling. We placed the siren in the dash below steering column blasting right into the driver's face, it does not impede the range of motion of the tilt-steering.

Advantages of this setup:

• No second fob
• Remote start still works
• Can work in conjunction with a fuel relay immobilizer and an OBD lock.
• Provides layered defenses with a "live" dummy OBD, a siren, and an ignition lockout
• Only one wire severed, green/violet (I think? need to verify, I know it was pin 15) on the black BCM plug, for the ignition coil relay.
• Very low power draw with boards in "dark" mode
• Inexpensive
• If removed, will fail "open circuit" on the starter relay coil activation.
• Requires no special action to start the car normally, or instructions for someone else to start the car.

[CalgaryZL1]

Nice work, I love this kind of stuff.

[Capricio]

Originally Posted by CalgaryZL1

Nice work, I love this kind of stuff.

Installed demo video.

[slick3]

Originally Posted by Capricio

Installed demo video.

So... when do they go on sale?

[Capricio]

K9 Body Control Module X4 (the black one, under your driver's side dash)
Pin: 15
Color: GN /VT
Circuit: 5199
Run/Crank Relay Coil Control

[bandier]

Not sure with the last post meant, but I'm ready for more info on this project.

[Capricio]

Originally Posted by bandier

Not sure with the last post meant, but I'm ready for more info on this project.

It identifies the one wire you need to sever to put the timer activation relay in line with the ignition. If you watch the in-car video, inside the hole on the side of the dash with panel off, you can see a sticker that has a color legend for the order of the plugs going into the BCM. There are 5 or 6, all different colors. You want the wire that leads to pin 15 on the BLACK BCM plug.

Hopefully J will find time to finish up the schematic soon. Sorry it's taking a while. We also have a video that will describe how to configure the relay boards.

[Curr]

Originally Posted by Capricio

It identifies the one wire you need to sever to put the timer activation relay in line with the ignition. If you watch the in-car video, inside the hole on the side of the dash with panel off, you can see a sticker that has a color legend for the order of the plugs going into the BCM. There are 5 or 6, all different colors. You want the wire that leads to pin 15 on the BLACK BCM plug.

Hopefully J will find time to finish up the schematic soon. Sorry it's taking a while. We also have a video that will describe how to configure the relay boards.

No worries take your time, I'm sure everyone appreciates all the time and effort you guys are putting into this in your spare time.

[bandier]

Cool. Thanks man. Can't wait!

Originally Posted by Capricio

It identifies the one wire you need to sever to put the timer activation relay in line with the ignition. If you watch the in-car video, inside the hole on the side of the dash with panel off, you can see a sticker that has a color legend for the order of the plugs going into the BCM. There are 5 or 6, all different colors. You want the wire that leads to pin 15 on the BLACK BCM plug.

Hopefully J will find time to finish up the schematic soon. Sorry it's taking a while. We also have a video that will describe how to configure the relay boards.

[Capricio]

Schematic:




I highly recommend building this out on a bench before trying to install in the car. Just need a battery source, ground, and multimeter testing continuity where the coil activation wire would be.

Also, if you're going to suffer through standing on your head in the passenger footwell to install a reset button like we did in the glovebox area, now is a great time to consider installing a footwell lighting kit (for cars with ambient lighting kits) and/or getting after the OnStar board.