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[Green Jeep]

Hi,

I need to know where the key transponder is for my Cherokee XJ 2001.

I have an ECU fault and have bought a second hand one but need the other part as well and the breakers aren't sure where its located.

As ever thanks in advance Maf

[Panic mechanic!]

if its like the wj its built into the igniton barrel/lock.

[tedthefed]

If its what i think it may be in the roof console because when i bought and ECU i asked for the other bits from the roof console.

[Mike Pavelin]

The SKIS module is in the steering column and wraps around the ignition lock.

[Green Jeep]

The SKIS module is in the steering column and wraps around the ignition lock.

Many thanks

[Lukemagnum]

The SKIS module takes about 5 minutes to change, 1 Torx screw and a multipin connector, although its not quite that simple, as the replacement one will have been programmed with the transponder embedded in the ignition key.

If you're changing out the SKIS, then you will need the keys that came with it, problem then is that these won't fit your ignition barrel - or your door locks. Your old keys can't be re-programmed as they can only programmed once when new.

As a temporary measure (and to check everything works with the new ECU) you can tie wrap the key onto the aerial of the SKIS (the loop that goes around the ignition barrel) and tuck the SKIS module down the steering column shroud, any key fitting the barrel will then start the engine. Be aware that you will effectively not have an immobiliser on your Jeep and your insurance Co. could take a dim view if it got nicked (although nothing new there).

The permanent way is to get a couple of new keys with transponders and have them cut to your original key and programmed as the replacement key you got from the scrappie. A good auto locksmith can do that for you if you don't want to remortgage your house and go to the stealership.

 

[nav18tor]

OK, so there is not a lot on telly, so as usual, I am surfing, and came across this

AD38 Chrysler / Jeep / Dodge Skim Pin Bypass

When carrying out key programming, ECU and dashboard replacement, the independent aftermarket always struggles when the system is protected by a security pincode.

The AD100Pro and MVPPro will read or bypass many pincodes using the "onboard" software, however on some vehicles this is not possible.

The AD38 Chrysler / Jeep / Dodge Skim Pin Bypass expands your abilities by overwriting the pin code on Chrysler / Jeep / Dodge Can systems.
Only - £319.00

At just over £300, it seems to good to be true

http://www.hickleys.com/diagnostics/ad38.php

http://www.advanced-diagnostics.co.uk/pdf/ad38_leaflet.pdf#454301

[nav18tor]

Could this UK based company solve the problem of SKIM ?

http://www.atpelectronics.co.uk/pages/ecu-decoding.html

[Mike Pavelin]

Lukemagnum. "Your old keys can't be re-programmed as they can only programmed once when new" this is incorrect, Keys are not programmed, the SKIS is programmed to accept the keys.

Navi8tor. You seem obsessed with this. SKIS very rarely malfunctions. Were you frightened by a transponder key as a child?

[Lukemagnum]

From the FSM:

When ignition power is supplied to the SKIM, the SKIM performs an internal self-test. After the selftest is completed, the SKIM energizes the antenna (this activates the transponder chip) and sends a challenge to the transponder chip. The transponder chip responds to the challenge by generating an encrypted response message using the following: 
Secret Key — This an electronically stored value (identification number) that is unique to each SKIS. The secret key is stored in the SKIM, PCM and all ignition key transponders. 

The transponder uses the crypto algorithm to receive, decode and respond to the message sent by SKIM. After responding to the coded message, the transponder sends a transponder I.D. message to the SKIM. The SKIM compares the transponder I.D. to the available valid key codes in SKIM memory (8 key maximum). After validating the key the SKIM sends a CCD Bus message called a “Seed Request” to the PCM then waits for a controller response. 



My understanding of this, is that the transponder in the key needs to be programmed with one of the 8 matching ID's stored in the SKIM EEPROM.

The transponder Chrysler use is a 4D 64 which once programmed with an ID can not be reversed (reversible transponders are available), this is why when replacing a key, a virgin transponder needs to be in it and a used key can not be reprogrammed to another SKIM.

[Jonny Jeep]

You can't just swap the SKIM for a new one without replacing the paired PCM. The SKIM learns the vehicles VIN from the PCM when first installed. The pair then  use a rolling code algorithm to prevent swapping of SKIM or PCM.

At just over £300 the AD38 is too good to be true. It reprograms a new pin to the SKIM, but you still need a DRBIII module to be able to program new keys to the SKIM.
The atpelectronics website doesn't list any Jeep models either.

[Mike Pavelin]

"My understanding of this, is that the transponder in the key needs to be programmed with one of the 8 matching ID's stored in the SKIM EEPROM."

No, the SKIS module is programmed to recognise the key. It can store up to 8. These can be deleted (all at once, not individually) and replacement keys stored.

[nav18tor]

Lukemagnum. "Your old keys can't be re-programmed as they can only programmed once when new" this is incorrect, Keys are not programmed, the SKIS is programmed to accept the keys.

Navi8tor. You seem obsessed with this. SKIS very rarely malfunctions. Were you frightened by a transponder key as a child?

I may have become a little obsessed, but I have no idea why, just something to fill my time......

[Lukemagnum]

When a vehicle is assembled the SKIM is programmed with a 4 digit code, the VIN and the ‘rolling code’. So yes, you are correct in saying that the SKIM is programmed to recognise the key, but the transponder in the key needs to be programmed so it can send back a response that the SKIM will recognise. When you marry up a new key with the SKIM, the key needs to be programmed to match the programme burnt into the SKIM, you do not change any of the programming in the SKIM other than the SKIM giving it a designated key number 0 to 7.

Further to this, it is the SKIM that has the rolling code imbedded in it, if you could get a new ‘off the shelf’ PCM there won’t be any security info in it, when you fit it to the vehicle the SKIM will then write its codes to the PCM leaving it permanently burnt in, it’s the SKIM that’s the master not the PCM. I don’t know about Chrysler, but it usually happens automatically on initial power up, without the need of a scan tool (Not recommended though).

As for Nav18tor’s AD 38 tool, all it does is change the 4 digit code in the SKIM. It doesn't trouble shoot, it doesn't programme new keys and it doesn't change the rolling code to the PCM, so I’m not too sure why you would need it. The 4 digit code is needed to programme a new key, a number of tools are available that will pull off this code, it is also in the main agents database for your vehicle, so if you changed it, you would have your local dealer stumped, it would also render all your current keys useless. Probably its only use is for resetting the SKIM if you've had all 8 possible keys made and you've lost them all.

Maybe it’s not an obsession Nav18tor but you’re shit scared of the electronics baring you from starting your car one morning and you have to get the bus!

[nav18tor]

Maybe it’s not an obsession Nav18tor but you’re shit scared of the electronics baring you from starting your car one morning and you have to get the bus!

Pretty much spot on, have not found my Jeep yet, (need to get rid of Jaguar first), but when I do have a XJ, at least I will be prepared for any issue's that it may have

My positive thoughts say, I will have no problems, but then there is that thing called "reality" waiting for me

[Lukemagnum]

I was mistaken nav18tor, since you don't own a Jeep then you really must be obsessed. 

Reminds me of the woman who wrote to Top Gear complaining that her husband insisted on taking his Vauxhall Cavalier Haynes manual to bed every night, then went on that she wouldn't have minded but he didn't even own a Vauxhall Cavalier.

[Mike Pavelin]

When a vehicle is assembled the SKIM is programmed with a 4 digit code, the VIN and the ‘rolling code’. So yes, you are correct in saying that the SKIM is programmed to recognise the key, but the transponder in the key needs to be programmed so it can send back a response that the SKIM will recognise. When you marry up a new key with the SKIM, the key needs to be programmed to match the programme burnt into the SKIM, you do not change any of the programming in the SKIM other than the SKIM giving it a designated key number 0 to 7.

Further to this, it is the SKIM that has the rolling code imbedded in it, if you could get a new ‘off the shelf’ PCM there won’t be any security info in it, when you fit it to the vehicle the SKIM will then write its codes to the PCM leaving it permanently burnt in, it’s the SKIM that’s the master not the PCM. I don’t know about Chrysler, but it usually happens automatically on initial power up, without the need of a scan tool (Not recommended though).

As for Nav18tor’s AD 38 tool, all it does is change the 4 digit code in the SKIM. It doesn't trouble shoot, it doesn't programme new keys and it doesn't change the rolling code to the PCM, so I’m not too sure why you would need it. The 4 digit code is needed to programme a new key, a number of tools are available that will pull off this code, it is also in the main agents database for your vehicle, so if you changed it, you would have your local dealer stumped, it would also render all your current keys useless. Probably its only use is for resetting the SKIM if you've had all 8 possible keys made and you've lost them all.

Maybe it’s not an obsession Nav18tor but you’re shit scared of the electronics baring you from starting your car one morning and you have to get the bus!

Sorry, but you're wrong.

The secret key data and VIN can be over written in the PCM once you have the PIN from Chrysler, and a DRBIII scan tool. The SKIS module does not do it automatically, if there is a mismatch in modules the car won't start. Both hold the secret key data and PIN, so either module can be replaced individually. You can delete all keys and install up to 8 new keys as many times as you like, or add keys to the current set. Once the SKIS is in programming mode you simply put a replacement key in the ignition, tell the SKIS to recognise it, they handshake, and you move on to the next one. You can install a new or used PCM, another SKIS module or both, as long as you do them one at a time and ahere to the correct procedure. I have done this myself on several occasions.

[nav18tor]

I was mistaken nav18tor, since you don't own a Jeep then you really must be obsessed. 

Reminds me of the woman who wrote to Top Gear complaining that her husband insisted on taking his Vauxhall Cavalier Haynes manual to bed every night, then went on that she wouldn't have minded but he didn't even own a Vauxhall Cavalier.

Paranoid, sad, bored!!!

It all started when I looked at a Jeep that would only run for 3 seconds at a time, I was/am determined to find a sensible solution even though that particular Jeep is long gone

[Mike Pavelin]

It's simple. SKIS was optional in the 'States, so you just get a non SKIS enabled PCM off ebay.com. Plug and play.

[nav18tor]

It's simple. SKIS was optional in the 'States, so you just get a non SKIS enabled PCM off ebay.com. Plug and play.

Thanks, will remember that

[Lukemagnum]

Why mess with ebay for something that may or may not work when you can reprogramme either module using the DRBIII? I see you can pick one up for a few grand so there must be a number of specialists out there who have got one. You’ll also be unlikely to find one in the States for a diesel, they think the devils fuel is for buses and tractors only.

BTW, thanks Mike for putting me straight on a number of items, I do appreciate it. I’m new to Jeeps and my knowledge is based on other makes, they all use the same principles but have their own quirks, but I’m always willing to learn.

[Mike Pavelin]

If you have a diesel the SKIS is the least of your worries.