Ignition key question - yet why are house keys so easily understood?

[VIPR PWR]

Good to know .. should be put in the DIY section

 

[HemiLonestar]

Outstanding info HemiLonestar!
I always wondered how it worked. You explained it really well.
The ignition key I have doesn’t match the code from Dodge. I want the code exactly the same to match the correct door code/key (i.e. I don’t want to carry two different keys).

One thing I don’t understand is, the SKIM is hard coded to the PCM, and I assume the only way to recode the PCM with a new key code is to send it in, which would cost a fortune.

However, since the transponder in the key head is programmable (per the owners manual), the only thing I think I need is a new transponder chip (which they say is a 4D 64). What I’m not sure of is can that chip be reprogrammed? Kind-of like your computer memory, you have Read Only Memory (ROM) which can never be reprogrammed because the code (IOS) is “burned into the chip”, and you have Random Access Memory (RAM) which is where all your downloads temporary stores stuff and it can write over-and-over again.

So can a key head transponder be reprogrammed?

You aren't coding the key to the PCM nor recoding the PCM, you are coding the key to the SKIM. The key itself is not programmable; what you are "programming" is the SKIM to detect new keys. Only thing that directly interacts with the PCM is the SKIM. The key is not a transponder, it does not send an active signal (passive). The SKIM actively scans for the chip and detects if it is there.
What you need to do to have everything match (key code wise) is replace (or if it can be re-keyed) your ignition switch, then have new keys cut and programmed to the truck. That's it.....or you can get the correct ignition switch, use your non-chip key to turn the switch and have one of the old (still programmed) chip keys hanging off the same key ring. Either way, you have to change the ignition switch itself.

Can the key system be bypassed.. I’m sure someone can figure that out

Only way to somewhat bypass it is to stash a key inside the column (seen this done for remote start installs). Otherwise no. It can however be removed, but that involves removing the SKIM and completely replacing the PCM.

People are saying you can remove the transponder from the key, and tape to the inside near the lock by just going through the gear shift rubber boot.
You won’t have the protection of the transponder then, but in today’s era, thieves just crack the steering column anyways and just tow the truck away.
I want to keep mine just as it came from the factory.

That's been done for remote start installs (or just stash a key/key head in there).

 

[Wifey]

You aren't coding the key to the PCM nor recoding the PCM, you are coding the key to the SKIM. The key itself is not programmable; what you are "programming" is the SKIM to detect new keys. Only thing that directly interacts with the PCM is the SKIM. The key is not a transponder, it does not send an active signal (passive). The SKIM actively scans for the chip and detects if it is there.
What you need to do to have everything match (key code wise) is replace (or if it can be re-keyed) your ignition switch, then have new keys cut and programmed to the truck. That's it.....or you can get the correct ignition switch, use your non-chip key to turn the switch and have one of the old (still programmed) chip keys hanging off the same key ring. Either way, you have to change the ignition switch itself.

Only way to somewhat bypass it is to stash a key inside the column (seen this done for remote start installs). Otherwise no. It can however be removed, but that involves removing the SKIM and completely replacing the PCM.

That's been done for remote start installs (or just stash a key/key head in there).

Genius! Thank you!

 

[2005ViperRam]

I bet they don’t do that in gang infested areas. Heck I’d slit their tires and other things just to serve as a warning to the tow truck drivers.

 

[2005ViperRam]

The key is not a transponder, it does not send an active signal (passive).

Just so I understand the terminology, the Texas Crypto 4D64 chip used in the key everyone on Google calls it a transponder chip. What is the true name of what kind of chip is it?

 

[VIPR PWR]

I bet they don’t do that in gang infested areas. Heck I’d slit their tires and other things just to serve as a warning to the tow truck drivers.

No doubt about that .. I live in a state that has stand your ground lay and allows citizens to protect self and property .. As far as m concerned a sneaky ass midnight grab with a tow truck is nothing but a POS person ,,, their sneak thieves and deserve anything they get .. the kind that would steal candy from a baby ..
Imagine waking up in the middle of the night and have an emergency and have to get to the hospital fast just to find your car is gone with no idea where it is …