• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Deleting Sentry Key System:

zluster

NAXJA Forum User
Location
Colorado Baby!
This information is mostly just for reference as I've already solved my problem.

I was working on a 01 WJ that refused to keep a programmed transponder key. The key would be programmed, correctly work, and then 24 hours later the key would act like it were programmed. Then if you programmed a new key both the new and the old would then work. I'm pretty sure the problem rested with the SKIM receiver. Thats the little box that has the antenna ring that sits around they key tumbler, reads the key code, and communicates with the ECU via the data bus.

The SKIM unit has a PIN number to accept a new key programming, as well as a "secret code" that is stored in the SKIM that the ECU needs to see as OK. (This is so that you can't just plug in a SKIM with a correctly programmed key to bypass the sentry system, the whole thing has to jive from key to transponder to ECU. This is all very easy to program and replace new parts as the secret code can be read via DRBIII or starscan, put into a new SKIM, and then the key programmed with the vehicle PIN. But if your like me you cannot afford $4000 for a DRBIII.

So since I needed to replace a SKIM module, which meant either finding a DRBIII to use and replacing the parts and doing the work myself, or towing it to a dealer and paying out my arsehole for something that I could easily do myself with the correct tools, or find a early 99 WJ ECU that did not have the sentry key system(or dish out a bunch of money for a new ECU from jeep that would also not have the sentry key system enabled).

Basically the SKIS circuit in the ECU is dormant until the SKIM is plugged into the data bus, when the SKIM module is plugged into the data bus the SKIM circuits are permanently activated in the ECU. No dealer will be able to deactivate them.

So if your like a friend of mine trying to diagnose a weird problem on your GFs jeep and you decide to take out your ECU and drop it in hers, only to realize that since she has the SKIM system you just permanently bricked the ECU for use in your own vehicle.

So that being said after some digging around I found a company that offers various ECU tuning services, including sentry key delete. So I sent in my ECU and $125 and a week later I got back an ECU and dropped it into my Jeep. With the SKIM now removed from the vehicle(actually just unplugged form the data bus for now) the Jeep starts up and runs just like it would if the SKIM system was working properly, or like a Jeep without the SKIS/SKIM system.

So for anyone in a similar boat it may be a most cost effective solution to have the SKIS/SKIM system deleted from the ECU. I paid a mobile locksmith $113 to program the existing transponder key I had, and then $20 the next day for another key he tried to program. (both times the key stopped working within 24 hours).

So had I originally just opted to delete the SKIS/SKIM it would have cost me less in the end.

The company that offers this service is http://autocomputerperformance.com/ And it sounds like they also offer some cool custom ECU options for guys doing modding or engine swaps.
 
Interesting that the SKIM circuit lies dormant in the ECU like that. Cool, good to know info...
 
Interesting that the SKIM circuit lies dormant in the ECU like that. Cool, good to know info...

Yup, so if you do need to get a Jeep started with the SKIM system you need only unplug the SKIM from the data bus and then drop in a non-SKIM enabled ECU until you can get the key programmed.

So if your jeep were ever wrecked and the ECU busted, you could borrow one out of your other jeep temporarily just making sure to unplug the SKIM before doing so.
 
Back
Top