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Tim's Auto Repair
Tim's Auto Repair, Mechanic
Category: Chrysler
Satisfied Customers: 16027
Experience:  Have owned a repair shop for 25 yrs.
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Chrysler Town & Country ex: 2003 Chrysler, Town & Country.

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2003 Chrysler, Town & Country. While driving all of the warning lights came on, everthing seemed ok, no engin hesitation or unsual noises. After arriving at my destination when it was time to depart the van would not start. This has happened, at least twice,before and the only accessories on at the time was the headlights and the air conditioner. [the vhicle mystirically starts after several]

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Customer: replied 5 years ago.
I am still waiting for an expert to answer
the first thing you need to do here,,is to load test the battery and the charging system,,,if you dont have a load tester,auto zone and most parts stores will do a load test for free,,
from the way you explain your problem,,it sounds as if you may have a failing alternator...
the load test will determine if it is infact a bad alternator

Please RATE my answer by clicking the RATINGS button, so I can get credit for my work,,the [BAD SERVICE] and [POOR SERVICE] rating does not give me credit].i don't receive commission if you give a less than 3 star/smiley rating ..I'm not always going to be giving you good news,so please don't let this stand in the way of you accepting my does not cost you more money.we will still be able to communicate.please understand,i can not see,hear or touch the vehicle and only know what you tell me. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.if i have sent any diagrams,please print them.they will only stay on here for an hour or so...sometimes you may need to right click the image,then save picture as]to save it to your computer so you can open it with your picture program...PLEASE ASK IF YOU NEED MORE HELP

Tim's Auto Repair, Mechanic
Category: Chrysler
Satisfied Customers: 16027
Experience: Have owned a repair shop for 25 yrs.
Tim's Auto Repair and 2 other Chrysler Specialists are ready to help you
Customer: replied 5 years ago.
Would a "failing' alternator cause the vehicle not to start even with a jump start?
did the starter turn the engine with a jump?
when it wouldnt start...was the alarm/security light on?
Customer: replied 5 years ago.
No, it did not start with the jump & yes the alarm/security light is on.
does te gages work?
does the gear selector in the instrument cluster light up?
Customer: replied 5 years ago.
The security/alarm light is on and the vehicle will not jump start
are you using the original key?
the theft deterant is on,,this is why it wont start..
try using a different key
2003 Chrysler Truck Town & Country V6-3.8L VIN L
Antitheft and Alarm Systems Description and Operation, Components: System Description, Sentry Key Immobilizer System (SKIS)
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.

Customer: replied 5 years ago.
, Thank you for your assistance. I understand somewhat the issues that may exsist the security system however there was no mention of the cause or possible repairon on this matter.