QuestionHi Roland,
I have been trawling the web for information concerning a Chrysler Voyager 3.3L, year 1997. It is a UK model and I have purchased the Chilton repair manual from the States. To complicate the overall picture I am British and now live in ‘very rural' France. My previous skills were in auto electrics for a few years so I am familiar with the general theory of immobilisers and electronic/electrical systems.
In this vehicle, the immobiliser system has caused problems over the past few months and I could not get the vehicle started without locking and unlocking the car several times with the remote control. At one point the immobiliser would not disarm so I tried new batteries in the remote, and again it failed to start until cleaned the battery contacts in the remote, which cured the fault for a month or so. Eventually the day came when I could not disarm the immobiliser and the Chrysler agent in Agen (SW France) diagnosed a new remote control unit. I paid the money for the new unit and the problem was still the same. They then said that the receiver unit may be faulty, but I did not want to take the chance they would diagnose the fault incorrectly a second time. It would the BCM module next, then the central locking unit etc, etc …..
Having some electrical I decided to bypass the likely immobilised circuits and restore the power to the starter motor and fuel pump circuits. This was partially successful in that I can start the vehicle but it will only run for a couple of seconds and then just dies. I have located the Immobiliser under the passenger's dash canopy and have a colour codes 8-way connector. When I worked at Lucas Service UK we had plenty of information concerning these circuits and manufactured bypass plugs to override the immobiliser/alarms circuits. Do you have any information that could assist me with this problem? The Chilton book does not provide circuit detail of this system in the wiring diagrams. I have read a forum in the States that stated once the car is running the unit can be removed and the vehicle will default to normal running.
I am sorry this has been a somewhat lengthy email. I do hope you can provide me with some assistance with this problem.
Regards – Mike Lloyd
AnswerHi Mike,
I don't have the '97 van shop manual but have pieced together some info from other manuals that may be of help. I think you have a good idea of how the system works, but you have to disable the alarm system in order to get it to run beyond a second or so, which is the normal anti-theft system functioning. Here is an answer I put together a few months ago for another van owner:
You know the one component I am always suspicious of is the body controller which has a central role in the body electrical systems. One thing that happens to it is that water can drip down on it and short circuit some of the conection pins/sockets together that then creates strange electrical "gremlins". The same might be true for the vehicle theft system unit that is typically mounted behind the glove box. If the car was subjected to a heavy rain or a car wash just before this happened that would be a reason to suspect this sort of a problem.
The body computer is located to the right of the steering column down near the floor under the dash. It is a rectangular thin box with two large plugs on one of the edges with colors blue and natural (whatever that means?) When you find it, simply disconnect the plugs and look at the pins and the sockets to see if you find any water or crud. You might but a spray can of electrical contact cleaner at an electronics store and spray both the plugs and the sockets.
The vehicle theft alarm module is behind the glove box usually and may require removal of the box to get at it. It too has two plugs, each with 8 wires. Now here it is very important that if you want to check this unit for similar water intrusion that you first start the engine and have it running when you disconnect the plugs so as to not put the vehicle in a "hard" engine shut down mode that can only be cured with a Chrysler diagnostic code reader box. So always be sure to have the engine running if you disconnect the vehicle theft system. Once you do that you can turn off the engine and you can if you choose just leave it unplugged which will also possibly solve the problem if the body computer cleaning hasn't already fixed it. Of course the system will no longer function, but at least that will solve the flashing. You can of course plug the system back in after you clean its plugs, even without the engine running, and then see if the system acts up again. I believe that it may not begin to function again until 20 engine cranks.
Finally, there may be a diagnostic self-test you can run on the system, at least this was so in the mid-90's and it may help localize the cause of the problem if it involves one of the other parts of the system.
A diagnostic mode is available in the system to verify operation of all monitored switches or circuits. To enter diagnostics, cycle the ignition key to the accessory position 3 times, leaving the key in this position.
Upon entering diagnositics, the park and tail lamps will begin flashing to verify their operation. In addition, the horn will sound twice to indicate that the trunk key cylinder is in its proper position. Returning the ignition to the OFF position will stop the lamps from flashing while keeping the system in diagnostics.
While in diagnostics mode, a horn pulse should occur at each of the following events indicating proper operation:
(1) Beginning with all doors closed, open then close each door. The horn will sound when the door ajar switch closes, and then again when the switch opens. There must be a 1 second delay between closing and opening the switch.
(2) Open, then close the hood. The horn will sound when the hood is opened, and again when it is closed.
(3) Activate the power door locks in both the lock and unlock directions. The horn will sound after each activation.
(4) Rotate the key in each of the door lock cylinders to the unlock position. The horn will sound as the switch closes, and again when it opens. There must be a 1 second delay bwtween changing switch states, or the horn will not sound.
(5) Cycle the key to the ignition RUN position. A single horn pulse will indicate proper operation of the ignition input. This will also take the module out of diagnostics mode. For any of these tests, if the switch does not remain open or closed for at least 1 second, the horn will only sound once.
The lack of a horn pulse, during any operation, indicates a switch failure, the lack of that input in the Vehicle Theft Security system module, or a failure internal to the module. Check for continuity at the switch, if this is good, check for an open or shorted wire between the switch and the alarm module. Also, check if the SBEC has been replaced recently. Vehicle Theft Security System will not function until 20 engine cranks.
So please let me know how some of these ideas work out for you and best of luck.
Roland
