[BhaskarG]

What should be the boot lock-unlock logic in modern cars to prevent lockout?

This post is only about boot locks, and getting locked out via the boot. A recent incident prompted me to write this:

I had gone for a trek to a remote hilly part of the country, some 350-400 kms away from the city, a place where the nearest bazaar is a minimum one hour drive away.

I drove till the last motorable road, and then I parked and locked my car (Venue SX+ DCT) at the base camp for the trek. I carefully placed the car key inside my trekking backpack, and started climbing. By 5:30 in the evening, I returned from the trek, exhausted, finally relieved at the prospect of resting in the comfort of the car. I pressed the boot door button, and the boot opened without a fuss. I took out a clean towel and water. Wiped my face, and then put back the towel along with my backpack inside the boot. Then I closed the boot. Car indicators blinked showing that it is locked. The car got locked with the key inside the backpack.

It was already in my knowledge that the boot door of Hyundai Venue gets locked/unlocked independently if the key-fob is nearby. But I was pretty tired from the trek, and these things escaped my mind.

The car did not detect that the key-fob is inside, and locked me out on a remote land with no sign of help. finally after futile trial of some common old-school methods for some hours we had to break a glass, to rescue the key-fob from my backpack.

There was the option of unlocking through Bluelink, but my phone was in the back pack, too!

After coming back to my city, I have looked around a little, and seen the following types of mechanical/electronic/software logic for boot door lock-unlock in common modern cars. Let us see which boot is better at preventing such incidents:

Type 1: No external mechanism to open the boot. Only way to open is using the lever at the base of the driver's seat. Usually seen in budget cars with/without central locking. Example: Datsun Redi-go. You cannot get locked out here (unless you circumvent the central lock). Because to open the boot, either the car as a whole has to be unlocked, or someone has to be inside.

Type 2: Contains external keyhole at the boot door. Example Maruti Alto, Hyundai Santro. However, boot door is independent of central lock, and hence not lock-out proof. Car can get locked with the key inside (similar to my incident, but less probable, because you need to have the key in your hand to unlock the boot in the first place).

Type 3: Dedicated button/function for boot unlock in the remote. Basically an wireless version of Type 2.

Type 4: Contains external button/lever at the boot door, but no key hole or any other direct way to unlock the boot independently. Boot door is part of the central locking system. Example: Hyundai Grand i10. This is the best logic, in my opinion. Because the boot is unlocked only if the central lock is unlocked. Similarly boot is locked along with the central lock. No way to forget the keys inside.

Type 5: Proximity sensor based independent boot unlock. That means, the boot is unlocked independently if the key-fob is nearby, while the other doors remain locked. Example: Hyundai Venue SX+. This is convenient feature for grocery shopping, but it is also true that the car gets locked back when you close the boot, without you pressing anything. In the Venue the car gets locked even if the key is inside. The lock should have been prevented if the key was detected inside.

Others: Luxury cars might have more sophisticated logic, that I do not know about.

What might be a best logic for the boot? Boot lock should be independent of central lock or not? What could have been be the soft/hard logic that could have prevented my unfortunate incident above?


Note to the mods: There is another topic in the forum about such lock-out scenarios, where the key is inside the car. And another about how to carry spare key-fobs with proximity sensors. Mods may merge this particular post, if required. Thanks.

[GTO]

My 530d has it simple & best. You can choose to "unlock all doors" whenever the boot is opened via the smartkey. I have enabled the option. So, even if you leave your key in the boot, you can open it again from the unlocked cabin.

This is simple & fail-safe.

[HighRevving]

The best thing to do here is follow one golden rule - Always keep your car key in your pocket!

Adding more and more technology to make the boot door open even when the key is at a distance, will only start making cars easier to steal. Imagine you pass by the boot of your car and it is open the whole time and an armed robber climbs in the boot - apartment security guards don't even check the boot. This situation can escalate quickly with women and kids or in the night. I personally don't even like keyless entry - I prefer to get really close to the car and unlock only the driver-side door (programmable in most Euro cars) when I am not at home. Unless you're at home and have access to the second key, I follow the golden rule while loading/unloading bags, changing to the spare wheel or working on fuses etc.

If someone is going for a swim or a trek, I can only suggest they wrap the key in a plastic bag and carry it in a bag or leave it with someone.

[Omkar]

Never really thought about this because I’m just paranoid when it comes to keys and locks in general. I’ll be always checking my pockets if I have the keys or not.

Originally Posted by BhaskarG

What might be a best logic for the boot? Boot lock should be independent of central lock or not? What could have been be the soft/hard logic that could have prevented my unfortunate incident above?

When it comes to locking mechanisms and their logic, and as far as manufacturers go, the primary goal will never be to prevent a lockout. It’s just assumed that car owners should be careful. Even the Venue manual repeats multiple times that the boot will lock itself automatically after 30 seconds unless it’s open.

However, I also believe with modern cars, we are seeing new ways to replace the typical key fob to lock/unlock the car and new solutions will come with time. For instance, BYD Atto 3 has an NFC key card that you can have in your wallet to unlock the car.


The MG Astor and the Hector facelift (2023) come with a Bluetooth-enabled sharable digital key feature. This feature allows 2 phones to be digital keys and you don’t need a physical key to drive the car. You can just use your phone to unlock the car and drive off. Correspondingly, the car unlocks / locks as you approach / leave the vehicle respectively.


In conclusion, not sure which logic is the best, but we will most likely have better solutions in the near future.

[RSMM]

My Ertiga 2022 has lever/flap along with request sensor button to operate tail gate. If FOB is kept inside after closing the tail gate and if request sensor button is pressed to lock the car, it will issue a warning beep and it will not lock. However, if one FOB is inside and you try to lock with other spare FOB, it will lock all doors. I have configured to operate all doors to unlock on one key press

[BhaskarG]

Originally Posted by Omkar

The MG Astor and the Hector facelift (2023) come with a Bluetooth-enabled sharable digital key feature. This feature allows 2 phones to be digital keys and you don’t need a physical key to drive the car. You can just use your phone to unlock the car and drive off. Correspondingly, the car unlocks / locks as you approach / leave the vehicle respectively.

My car is Bluelink enabled, through which I could have unlocked from my phone itself. But you know where my phone was . Also, service guys said that they could have unlocked it remotely, if only I could have shared the OTP.

Originally Posted by RSMM

My Ertiga 2022 has lever/flap along with request sensor button to operate tail gate. If FOB is kept inside after closing the tail gate and if request sensor button is pressed to lock the car, it will issue a warning beep and it will not lock. However, if one FOB is inside and you try to lock with other spare FOB, it will lock all doors. I have configured to operate all doors to unlock on one key press

Maybe the Venue did not even detect the key inside the boot! Also is the boot door configurable in Venue (like it is in your Ertiga)?

[audioholic]

In my Slavia if you keep the key in the boot and shut it, it opens within a second unless it detects a second key right outside the boot or any other request switch. Simple. Innova doesn't allow locking of doors from outside in the same condition.

The generic logic is, if there is a keyfob inside the cabin, locking and unlocking is only allowed from within the cabin either via the cabin switch or automatically upon crossing the threshold speed.

[Jeroen]

A couple of years ago I had an unfortunate experience with my Jaguar in France.

I managed to lock the Jaguar keys inside the boot! There was no way we could unlock the boot. With the help of a local garage we managed to open the cabin, but the electronic boot release would not work. Because it believed the car was broken into.

I have look all over the internet for a solution, but there simply is not one, at least not for my Jaguar. If you lock the car, then use the key fob to open the boot and somehow manage to leave your key inside, you are done for it.

My solution was to get my son to drive over to our home, pick up a spare key and drive all the way to France to rescue me!

All described here:

https://www.team-bhp.com/forum/diy-d...ml#post4674311

When I go on long trips I usually take a spare key. I give it to my wife, or alternatively leave it in my luggage, so as long as the luggage is out of the car, I am good to go! My wife has a habit of loosing keys, so not a fool proof solution either.

I have also seen special little metal boxes that you can attach somewhere underneath your car that will hold a spare key.

Jeroen

[GeeTee TSI]

Indirect way out to try and address the root cause, avoid leaving the key fob behind by having a carbiner key ring attached to your belt hoops so that the key becomes a part of you

[sagarpadaki]

Originally Posted by audioholic

In my Slavia if you keep the key in the boot and shut it, it opens within a second unless it detects a second key right outside the boot or any other request switch. Simple. Innova doesn't allow locking of doors from outside in the same condition.

The generic logic is, if there is a keyfob inside the cabin, locking and unlocking is only allowed from within the cabin either via the cabin switch or automatically upon crossing the threshold speed.

I think Slavia has a key presence sensor in the roof of the boot which detects the presence of the key in the boot and prevents locking.

IMO, all car makers beyond a certain price point should provide this kind of sensor in the boot to ensure such lock outs do not occur.

[Vibhanshu]

My Ford Fiesta 1.5 D (2014) has a "always unlocked from inside" logic. So I do have a lock/unlock button, but that for external control only.

From the inside, all doors are always unlocked.

For kids, there was a separate control on rear 2 door. I never checked or tested their mechanism.

I found this setup to be very good. Guarantees door operation during any adverse event.

[audioholic]

Originally Posted by sagarpadaki

I think Slavia has a key presence sensor in the roof of the boot which detects the presence of the key in the boot and prevents locking.
.

Yes there is an interior antenna in the boot but at the base of the rear seat which I encountered by chance last week. Should check the same in the Innova. I'm sure it doesn't allow locking of the car with key inside as well. The boot locks in a motorized way but can be opened by pressing the outside switch on the lid. But locking the car is a definite no.

[Kosfactor]

It is possible for other materials in the boot to interfere with the smart key.

The first time I tried putting the spare smart key in a metal box, car still detected it. Next time I kept the spare smart key under a laptop in the boot and the car will not detect it, happily locked the boot

It is a good practice to have a spare key anytime you are more than a hour from home, nowadays you can share the digital key \ app with your friend or partner , if there is network the car will unlock remotely.