[keep_hope_alive]

This is from the kill switch thread:

Originally Posted by keep_hope_alive

Has anyone thought about just hiding the OBD plug? Relocating it to an inconvenient location deeper under the dash?

What about cutting the wires and inserting a male/female DEUTSCH plug pair so the standard OBD plug is something you keep at home? This sounds like something I will do. Instantly eliminates access to the plug. better yet, leave the OEM plug but it won't connect to anything... further the frustration.

Originally Posted by keep_hope_alive

I've been thinking about this. While fuel is one option, intercepting the transmission park/neutral switch would prevent cranking entirely and won't throw a code. There are a few other ways to prevent a crank/start that won't throw a code. You have to assume that you will forget the super secret switch from time to time. I had a car stolen in 2016 and then added a hidden switch on the immobilizer circuit. It's a bummer that it defeats remote start ability. I didn't use it all of the time because I usually park in a garage or other safe location. As such, I commonly forgot to close the switch and would try to start the car. It didn't throw a MIL, but would crank with no start.

You don't want to just interrupt the starter relay (lifting the ground to that coil would be easy) because the ECM/BCM will assume a crank and send fuel. We want to safely prevent the car from starting.

From the service manual:

Keyless Start
When the Ignition mode switch is placed in the crank position, a discrete signal is supplied to the
body control module (BCM) notifying it that the ignition is in the crank position. The BCM then
sends a serial data message to the engine control module (ECM) that crank has been requested.
The ECM then verifies that the brake pedal is applied and for manual transmission the clutch is
fully depressed or for automatic transmission is in Park/Neutral. If it is, the ECM then supplies 12
V to the control circuit of the starter relay. When this occurs, battery positive voltage is supplied
through the switch side of the crank relay to the S terminal of the starter solenoid.

Key Start
When the ignition switch is placed in the Start position, a discrete signal is supplied to the body control
module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to
the engine control module (ECM) notifying it that CRANK has been requested. The ECM verifies that the
transmission is in Park or Neutral. If it is, the ECM then supplies 12 V to the control circuit of the crank
relay. When this occurs, battery positive voltage is supplied through the switch side of the crank relay to
the S terminal of the starter solenoid.

Originally Posted by keep_hope_alive

Schematic of the starting circuits with a few options noted. I have not tried intercepting this wire yet to see if it does what I think it does. I suspect the switch is closed in park/neutral and not open in park/neutral. This logic is important to verify.

Originally Posted by keep_hope_alive

I will review the transmission park/neutral sensor wire intercept concept, that I shared in an earlier post, when I install some additional USB power soon. I'll report back. This may be the easiest method for the AT folks but it won't help the MT folks. If the thieves have have OBD access, they could program out this interlock, but they won't expect to so it should trip them up enough. This (as do other concepts) eliminates remote start.