Dwrecked

I'm thinking about buying an 02 cherokee from a coworker. He says the battery went dead, tried to jump it, and the security system now won't turn off. Fob doesn't work. Could I just go buy a new fob to turn the alarm off? If not, are there any other suggestions?

My car was stolen last weekend and I really need a way bavk and forth to work.

Could thus be a bigger issue as well?

Cleman Simpson

Dave is the man for this, but I think sometimes the key will disarm the security system by locking and unlocking the door a few times. If the battery was dead for an extended period of time the computer may have lost its memory too.

Dwrecked

Looks like Dave's not here, man.

Cleman Simpson

Oh well, might as well fire one up and wait then I guess. LOL.

RRXJeeper71

any resolution?

dave1123

Sorry, Dave was asleep and getting ready to go to work.

A new fob will not work because it has to have it's code installed into the RKE transceiver. (remote keyless entry)

Does the alarm shut off with all the doors closed? Try locking all the doors and closing them, then unlocking the driver's door with the key. Until you figure this out, pull the horn fuse so the neighbors don't call the police!

There are actually 2 systems involved here, the security alarm and the engine immobilizer. Have you tried starting it with the key?

Can you tell I'm winging it here? I don't always have the answers, but I can point you to things to look for. This has come up so many times, I'm going to have to do some research for the definitive answers.

Dwrecked

Getting off work soon, gonna charge the battery and start trouble shooting. I'll update in a few hours.

I haven't messed with the jeep yet, if I can fix it I'm buying it.

My car was stolen last week so I'm really hoping I can fix it.

Dwrecked

Turns out the battery isn't in it. Gonna put one in. I read that it has to be a jeep key, no third party. Is this right, or is it possible a 3rd party will work?

Cleman Simpson

I managed to lose the only key I had to my 2004 Laredo and so I tried a 2007 Dodge Ram key I had left from a truck I traded off. to my total surprise it cranks the jeep and it runs perfectly, but it will not unlock the doors. I guess the ignition was worn down just enough to let the slightly different cut in the dodge key to work in it. I don't know what the odds were that the code in the key would work in the different vehicle but apparently The Lord made me accidentally keep that key for a reason, LOL.

Dwrecked

But will a third party key made for this jeep reset the security alarm?

Cleman Simpson

I think the codes are specific to each individual vehicle. I would guess you will have to take the vin number to a jeep dealer and get a key cut and coded there.

dave1123

Apparently the SKIM recognizes the key code for Cleman,

Dwrecked, Each jeep has 2 keys programmed into the Security Key Immobilizer Module, a grey one and a brown one. All other keys are black. An aftermarket key can be programmed into the SKIM either by the self-programming method using BOTH original keys or by the dealer with a DRBIII scan tool.

The way this works is all keys must have an RF chip in them. Each key has it's own code built into it and the SKIM needs to be programmed to recognize it. Both original keys have a "secret" code from the factory so the SKIM knows they are original. There are just so many codes so they are used over again in later years and different vehicles. That's why Cleman's key from the Ram works.

What the DRBIII scan tool does is read the key code, then transmits it into the SKIM. The SKIM can hold up to 6 key codes besides the 2 originals. When you insert a key into the ignition lock, the sensor around the lock interrogates the key and if the code matches one in it's memory, will allow you to drive it. If not, the engine will start, then shut down in seconds.

In a worst case scenario, you can buy a SKIM and 2 keys from the dealer. IDK what the price is!

dave1123

Okay, on the alarm system. If the alarm was set before the battery went dead, it will reactivate upon recharging the battery or installing a charged one. You can cancel it by using the fob or unlocking the driver's door with the key.

There are 2 modes for setting the alarm. A passive set will be done with the headlights off, the key removed from the ignition lock, and all doors locked with the power door lock system switch on the driver's door. If the driver's door is open when you lock it, the alarm will not set, even if you lock it with the key after closing it. An active set is done with the fob after everything is closed.

Try replacing the battery in the fob.