Fix Chrysler anti theft system
Chrysler anti-theft systems have gone through a few iterations. Starting in 1989, Chrysler started installing them on the C, G, and J body styles. The engine controllers in that era were referred to as SMEC (single module engine controller). The SMEC communicated with the body control module (BCM). In anti-theft equipped vehicles, the system would sense when you removed the ignition key. If you then used the remote keyless entry (RKE) to lock the doors, the SECURITY light would flash for 7-secs and then go out. The system was then armed. If the doors were opened without disarming, the horn would honk, parking lights would flash, and the SMEC would turn off the fuel injectors to prevent start-up.
While armed, the security alarm module (SAM) monitors the hood, trunk, door, and ignition switches via a data bus from the BCM. Some of the switches were hard wired to the SAM, others to the BCM. The SAM is programmed to look for a door unlock first. If it sees a hook, trunk, or ignition signal without first seeing a door unlock, it would set off the alarm. The horn is programmed to time out in 3-mins to prevent battery drain and avoid messing with your neighbors. The park and tail lights time out in 15-mins. Disconnecting the battery without first disarming will also set off the alarm system.
WHAT GOES WRONG
If you have a dead battery and you’ve charged it or replaced it, chances are good that the alarm is still in disable mode and you won’t get fuel. To reset the system, close the door and hood. Then lock and unlock the doors with the keyless entry fob or the actual key.
Chrysler updated the system in 1993 on the LH vehicles by incorporating the SAM module into the BCM. And then got rid of the SECURITY light and instead installed an LED to the middle of the dash. The LED flashes for 15-seconds and then every 30-seconds to alert would-be burglars that the system was armed.
Now here’s where you have to pay attention. Both the SBEC and the BCM of this generation are programmed to look at each other to see if the alarm programming is installed. This matters if you need to replace either component. Here’s the scenario; you grab an SBEC from the junkyard from the exact vehicle as yours, but that vehicle DIDN’T have an alarm. Now you try to install it in your vehicle. The SBEC checks in with the BCM that WAS programmed for alarm. Now you’ve got a problem. The used SBEC will not allow the vehicle to start.
Starting in 1995, Chrysler added another module called the SKIM (security key immobilizer). It works in conjunction with the alarm system. This system uses a transponder key and a transmitter/receiver module in the steering column. When you insert the key, the transmitter sends out a radio frequency. The radio signal is received by the antenna in the key and powers up the chip, which then transmits its unique I.D. code back to the transmitter. If the I.D. code isn’t correct, the vehicle will start and then stall and the security light will flash 6 times. If you repeat the starting procedure with the wrong key, the system will disengage the starter on the 7th attempt. The only way to unlock the system at that point is to use the proper key, or have the system reprogrammed with a factory scan tool or by doing a customer learn procedure.
CUSTOMER LEARN PROCEDURE
If you get a new key from the dealer, here’s how to program the system yourself.
You’ll need TWO working keys
1) Insert one good key in the ignition switch and turn it to ON. Leave in ON for 3-secs., and then turn it to OFF.
2) Insert the second good key and turn to ON. You must insert both keys withing 15-secs. After 10-secs. in the ON position, the security light will flash and the chime will ring one time.
3) Within 50-secs, remove the 2nd key and install the new blank key. Turn to ON.
4) Wait until you hear another chime and watch for the security light to stop flashing. Once the light glows steady for 3-secs, you can remove the new key. The key and the system are now programmed.
The system allows up to 5 keys to be programmed to one vehicle. If you replace the BCM, you must enable the alarm. On 1996-2000 minivans, follow this procedure: Open the hood and then cycle the key in the liftgate. On 1994-1997 LH vehicles, the system is self enabling. On all other, you need a factory scan tool
© 2012 Rick MuscoplatPosted on by Rick Muscoplat