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joseph carrillo
joseph carrillo, Auto service technician
Category: Dodge
Satisfied Customers: 448
Experience:  A.S.E. certified auto electrical , engine performance , advanced engine performance, emmisions
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2002 Dodge Caravan Sport: car starts..dies..airbag..steering wheel

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2002 Dodge Caravan Sport, car starts and after 5-8 sec. dies, skim module warning light comes on and frequently stays on and also the airbag warning light comes on. After several trys and by moving the tilt steering wheel up and down the car finally starts. What is problem? How difficult is it to repair? How much will it costs to repair?

ok here is a description of the system please read while i gather more info for you


The Sentry Key Immobilizer System (SKIS) is available as a factory-installed option on this vehicle. It is designed to provide passive protection against unauthorized vehicle use by disabling the engine, after two (2) seconds of running, whenever an invalid key is used to start the vehicle. The SKIS is active whenever the ignition is on and does not require any customer intervention.

The primary components of the system are:

  • Sentry Key Immobilizer Module (SKIM) Sentry Key (ignition key w/ a transponder molded into the head)
  • Indicator light
  • Body Control Module (BCM)
  • Powertrain Control Module (PCM)

When the ignition switch is turned on, the SKIM interrogates the ignition key. If the ignition key is Valid or Invalid, the SKIM sends a PCI Bus message to the PCM indicating ignition key status. Upon receiving this message the PCM will terminate engine operation, or allow the engine to continue to operate.

The SKIM is mounted to the steering column with the molded, integral antenna mounted on the ignition housing. The indicator light, is located in the message center.

The SKIS includes keys from the factory which are pre-programmed. Each SKIM will recognize a maximum of eight Sentry Keys. If the customer would like to own additional keys other than those provided with the vehicle, they can be purchased from any authorized dealer. These keys must be programmed to the SKIM on the vehicle in order for the system to recognize them as valid keys. This can be done by the dealer with a DRB III scan tool or by a customer if this feature is available in their market and they have two (2) valid keys already available to them. Refer to the Service Procedures portion of this system for additional details.

The SKIS performs a self-test each time the ignition switch is turned to the ON position and will store Diagnostic Trouble Codes (DTC's) if a system malfunction is detected. The SKIS can be diagnosed and any stored DTC's can be retrieved using a DRB III scan tool as described in the appropriate Body Diagnostic Procedures manual.

When ignition power is supplied to the SKIM, the SKIM performs an internal self-test. After the self- test 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 is 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.

Challenge - This is a random number that is generated by the SKIM at each ignition key cycle.

The secret key and challenge are the two variables used in the algorithm that produces the encrypted response message. The transponder uses the crypto algorithm to receive, decode and respond to the message sent by the 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 the SKIM memory (8 key maximum at any one time). After validating the key ignition the SKIM sends a PCI Bus message called a Seed Request to the engine controller then waits for a PCM response. If the PCM does not respond, the SKIM will send the seed request again. After three failed attempts the SKIM will stop sending the seed request and store a trouble code. If the PCM sends a seed response, the SKIM sends a valid/invalid key message to the PCM. This is an encrypted message that is generated using the following:

VIN - Vehicle Identification Number

Seed - This is a random number that is generated by the PCM at each ignition key cycle.

The VIN and seed are the two variables used in the rolling code algorithm that encrypts the valid/invalid key message. The PCM uses the rolling code algorithm to receive, decode and respond to the valid/invalid key message sent by the SKIM. After sending the valid/invalid key message the SKIM waits 3.5 seconds for a PCM status message from the PCM. If the PCM does not respond with a valid key message to the SKIM, a fault is detected and a trouble code is stored.

The SKIS incorporates a VTSS LED located on the instrument panel upper cover. The LED receives switched ignition voltage and is hardwired to the body control module. The LED is actuated when the SKIM sends a PCI Bus message to the body controller requesting the LED on. The body controller then provides the ground for the LED. The SKIM will request VTSS LED operation for the following:

  • bulb checks at ignition on
  • to alert the vehicle operator to a SKIS malfunction
  • customer key programming mode

For all faults except transponder faults and VTSS LED remains on steady. In the event of a transponder fault the LED flashes at a rate of 1 Hz (once per second) . If a fault is present the LED will remain on or flashing for the complete ignition cycle. If a fault is stored in SKIM memory which prevents the system from operating properly, the PCM will allow the engine to start and run (for 2 seconds) up to six times. After the sixth attempt, the PCM disables the starter relay until the fault is corrected.


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Common communication problems:

  • Two transponder keys too close together.
  • Speed Pass too close to transponder key.
  • Solid indicator that there is a system failure.

    • Loss of PCM communication.
    • Failed antenna circuit.
  • i believe that the problem is going to be with the antenna circuit which is integrated into the ignition lock cylinder , due to the fact that when you played with the steering column it started up , also the only way to extract trouble codes from the skis module is through a enhanced chrysler scanner , that only the dealer or repair shops have , this gives the direct code to the problem and eliminates guessing what the problem might be ( smart system )
Customer: replied 10 years ago.
I understand how the system works. What is my problem and what needs to be done to correct the problem? Why does my moving the steering wheel up and down temporarly solve the problem? Do I have a broken wire? Is the SKIM faulty? What else could be the problem? How difficult is it to replace the skim module and update the keys/

ok you must of not read my second post , like i said i believe that you have a radio frequency problem from the switch to the transponder , i believe that moving the steering wheel , might of done something.

BUT i cant say for sure that this is your problem , the skis system is a computer controlled system , the only way to know the problem that is affecting your vehicle right now is to have a chrysler enhanced scanner hooked up to the cars data link connector and communicate to the antitheft / skis module , this is the correct way to diagnose your problem ,once the trouble code is extracted then diagnosing can be done on the circuit that is affecting and triggering the skis system . you dont want to just start changing modules or parts of the system without knowing what part is the problem , that route can be very costly , and not to say time consuming , also you asked about the skim replacement well to do that heres what else needs to be done , this is not as easy and simple as you might think , it is a complicated computer system


  1. Turn the ignition switch ON (transmission in park/neutral).
  2. Use the DRB III and select THEFT ALARM, SKIM then MISCELLANEOUS.
  4. Program the vehicle four-digit PIN into SKIM.
  5. Select COUNTRY CODE and enter the correct country NOTE: Be sure to enter the correct country code. If the incorrect country code is programmed into SKIM, the SKIM must be replaced.
  6. Select YES to update VIN (the SKIM will learn the VIN from the PCM).
  7. Press ENTER to transfer the secret key (the PCM will send the secret key to the SKIM).
  8. Program ignition keys to SKIM. NOTE: If the PCM and the SKIM are replaced at the same time, all vehicle keys will need to be replaced and programmed to the new SKIM.


  1. Turn the ignition switch ON (transmission in park/neutral).
  2. Use the DRB III and select THEFT ALARM, SKIM then MISCELLANEOUS.
  4. Enter secured access mode by entering the vehicle four-digit PIN. NOTE: A maximum of eight keys can be learned to each SKIM. Once a key is learned to a SKIM it (the key) cannot be transferred to another vehicle. If ignition key programming is unsuccessful, the DRB III will display one of the following messages: Programming Not Attempted - The DRB III attempts to read the programmed key status and there are no keys programmed into SKIM memory. Programming Key Failed (Possible Used Key From Wrong Vehicle) - SKIM is unable to program key due to one of the following: