Idea: kill switch?

KiwiME · May 8, 2023

mtd said: ↑

I suppose you could wire something up in series with the fireman's loop which, no question, will immobilize the vehicle. I have no idea what collateral damage that would cause, or if it would be any different than disconnecting the 12 volt battery. Given the wire size the loop is likely some kind of low current control circuit.
Click to expand...

You'd want to interrupt some circuit that doesn't throw a code and that idea might work well. Via the BMS, that interrupts the 12V power to the (2) HV relays in the traction battery.

I tested the metal biscuit tin I'm using and the RFID part got thru as well when I was within range, specified as 0.7 m.

hobbit · May 10, 2023

Well, the first cut is in already. Interrupting one of the power leads to the shifter module
renders every button except "park" nonfunctional. So now a semi-hidden switch that I can
discreetly reach serves the intended purpose. The car still powers up and brings the main
pack online, which opening the fireman's loop would disable -- but that's an intriguing idea too.

If I power up the car with the switch opened, *sometimes* I get a "check EV system" warning
but everything operates normally once the switch is closed. The orange small EV-warning light
stays on for that power cycle, but nothing gets posted to OBD2 diagnostics.

A satisfactory proof-of-concept, and the wiring mod was very simple. I was able to do it on
the "car side" of the big connector serving the center console, and then run a simple twin-lead
to where the switch sits. So it doesn't interfere with center console removal at all.

_H*

Lars · Jun 8, 2023

Why not an iPhone app, with face (or finger print on others) recognition connects to the car - any car with enabling start?
Just saying. What is this difficult?

22kona · Jun 9, 2023

hobbit said: ↑

Well, the first cut is in already. Interrupting one of the power leads to the shifter module
renders every button except "park" nonfunctional. So now a semi-hidden switch that I can
discreetly reach serves the intended purpose. The car still powers up and brings the main
pack online, which opening the fireman's loop would disable -- but that's an intriguing idea too.

If I power up the car with the switch opened, *sometimes* I get a "check EV system" warning
but everything operates normally once the switch is closed. The orange small EV-warning light
stays on for that power cycle, but nothing gets posted to OBD2 diagnostics.

A satisfactory proof-of-concept, and the wiring mod was very simple. I was able to do it on
the "car side" of the big connector serving the center console, and then run a simple twin-lead
to where the switch sits. So it doesn't interfere with center console removal at all.

_H*
Click to expand...

What happens if the switch open ccts when you are driving, just wondering, would park engage?

KiwiME · Jun 9, 2023

The drive mode selection is done over CAN while Park and EPB seems to be done with discrete signals. I'd speculate that a loss of power to the CAN portion might prompt the car to disable drive power (effectively Neutral). I'm confident Hyundai would have considered the outcome of single point failure conditions such as the loss of power that the switch introduces on purpose, or if the electronics simply fails.

C02less · Jun 9, 2023

Is EV theft an issue? Where I live stolen cars usually get shipped to some banana republic without any charging network so they don't want EVs. According to a CBC article I read a while back.

Ferenc Jakab · Jun 9, 2023

KiwiME said: ↑

The drive mode selection is done over CAN while Park and EPB seems to be done with discrete signals. I'd speculate that a loss of power to the CAN portion might prompt the car to disable drive power (effectively Neutral). I'm confident Hyundai would have considered the outcome of single point failure conditions such as the loss of power that the switch introduces on purpose, or if the electronics simply fails.
Click to expand...

Not being an engineer I'm not sure if this is relevant. My recent 12V battery problems which were probably caused or possibly just exacerbated by reverse jumping led to a failure in a controller that sends signals to the fan to operate when necessary. This meant that the fan switched on and ran permanently as soon as the car was switched on. It has now been repaired. During the long wait for the appropriate part to come from Korea I pulled the plug on the box the fan motor is plugged into, plugging it back in when fast charging. I suppose what I'm saying is that in this instance the failure of a controller did not prevent the car from operating.

hobbit · Jun 14, 2023

Flipping the switch while under way has no effect, since the shift module isn't issuing commands at the
time. I believe there's a separate dedicated Park command lead, so that always works, although trying to
select Park while rolling at any significant speed only elicits loud warnings from the car.

[Selecting Park while rolling very slowly, though, slams the car into Park with the expected lurching,
which is why I installed a finger-guard over that button so I would be less likely to do that.]

_H*

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Idea: kill switch?

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