My Solution for OBD Reprogramming Theft

Last week or so someone posted about their truck getting stolen. We all had some pretty good ideas to deter someone getting into the truck, gaining access to the OBD port, programming some keys, bam truck is gone.

First you need to buy two connectors of the same type. It can be a 16 pin to match he OBD plug or as low as a 9 pin since that’s the factory count.

Next…hack off your OBD connector.


Then wire up one side of your new connector to the factory OBD connector. I scrambled them around so they didn’t match the factory config. I don’t have a good pic of this but picture the factory OBD connector as a different type.

You’ll still need an OBD connector so next step make an adapter. New connector on one end ODB on the other. Yes I blurted the pics. Probably didn’t need to but oh well. You get the idea.


Next up another decoy. This connects to your new OBD connector and some wires. Connect this decoy and zip tie the end up hidden somewhere.


This added wire makes it appear as something else and you don’t have an OBD port anywhere! I plan to cover the factory OBD bracket with a little message for any potential thieves.

This still won’t deter a very determined thief but to get around this you’ll have to fine the connnector, cut the wires, and rewire in a new OBD port.

And yes of course there is towing. That’s what a garage is for though.

 

Well, that certainly one way of doing it...


Personally if I had gone that route I would have just relocated the factory plug up higher tucked away somewhere, would be afraid of cutting factory wiring that critical, and then had the dumby decoy OBDII port wired up so all pins would short hot hopefully frying the smart tools of whatever jackass was trying to jack my rig.

If nothing else get them to scram when their tools weren't working.

I doubt significantly anyone attempting such wouldn't hang out to poke around under the dash if it didn't connect on the first try.

 

Last step, hope the obd++ port has protection diodes on every pin so you don't let the magic smoke out when someone plugs in a normal pinout.

 

Thats actually what I was going to do originally but once I had it pulled down there wasn’t much slack. I’m a little paranoid when it comes to theft and I have a fair amount of money into my truck. So anything I can do makes me feel better.


I’ve hacked many factory wires so wasn’t too worried about this one. It’s only nine wires and fried ECU if you get it wrong.

 

They’d have to show up with the same connector I have and have it wired just right to do that. However it’s a good idea.

 

and I thought I was paranoid

 

How do you figure that? Read my post again.

 

I think just tucking the factory plug up in there hidden and have a dummy plug there would work for me. Great idea, I'm definitely taking your idea and making it my own!

 

I guess I don’t understand your post. The only way to interface with my OBD plug is my special adapter. The adapter is the correct pin out for the factory OBD (otherwise it wouldn’t work).

 

Not really. This was maybe 20 minutes worth of work? Also when you have a modified vehicle stolen you tend to become a little more paranoid.

 

So do you not have to go through DEQ or are they okay with plugging into your special adapter when you renew your tags?

 

I plug in adapter, tuck it up into dash, hook OBD port (from the adapter) into the factory spot, ready for emissions.

 

You could also relocate a needed relay (like ignition) somewhere semi accessible and just take that relay with you everytime you left your truck. That way they could make as many keys as they wanted, but the truck wouldn't start.

Props for ingenuity OP!

 

What I am saying is that you have scrambled the pinout, if someone plugs a normal OBD device into your scrambled pinout, is there the possibility of feeding current into pins not designed to accept it? Thus frying the ECU.

 

Ditto

 

Nifty solution, but wouldn't it have been easier to just swap the power and ground circuits at the DLC (data link connector - that's the actual name for that "OBD plug") and leaving the rest of the pinout alone? SAE requirements are pin 16 is power, pins 4 and/or 5 are ground. Swapping 4 and 16 seems like a much simpler solution. Polarity reversal at the DLC would definitely be enough to stop anyone from using that method on your truck, and might even damage their equipment = Win-win.

If you use a 1-wire weatherpack connector on both the power and ground circuits, say 12" up the harness from the DLC, then it would be a quick 30 seconds to reverse it and look factory...without the convoluted adapter harness and all of that jazz. Don't get me wrong, your solution is definitely effective, but overly complicated IMO.

 

Well my adapter descrambles. So I’m saying if they were to do what you are saying they’d have to build an adapter using the same connector.

I worded that poorly. My new connector is similar to the rows on the OBD connector. So I mixed them up there so they weren’t laid out in the same manner.

 

If I have to hack up my OBDII port to not have my truck stolen, I'd move or let them have it. That's why I pay for insurance, including extra coverage for my add-ons. I can imagine a dealer trying to blame any number of issues on that mod when trying to get warranty work authorized. To each their own and I admire the OP for his expertise and ingenuity on doing a mod I could never do myself, but I personally would not go that far.

 

My truck is out of warranty anyway. Plus even if it wasn’t they’d probably laugh if I drove in for any sort of warranty work.

I also checked on the insurance thing. It ended up raising my payment something like 4-5x at least. High enough that it would have paid for those parts within a few years. Wasn’t worth it.

 

Adding a few thousand of accessory coverage didn't add a ton to my premium. Then again, this is Florida, so the premium is outrageous to begin with LOL