QuestionHi. I have a 97 Grand Caravan, 3.8L. Yesterday my dash lights became erradic. Check Enginer on, AlarmSet On, ABS On. Turned off car because theough it was glitch. THis time ABS on first, few sec later Alarmset goes on, sometimes check engine. No odometer displays at all, gauges do not operate. I read error code P1698 using tool.
Claims it is ECM (aka PCM?) or communication to TCM. I cleaned harnesses on TCM and ECM/PCM on inndr fenders. Wiggled visible cabels. Same issue. What is most likley cause? The ECM is special order from Autozone at $200, non-returnable, so want to make educated prioritizations first on what to replace. If I do replace ECM first, do I need special tool for setting mileage (not sure if stored here)? Please assist with a list of most likley cause. I have had BCM and other electrical issues many yuears ago when under warranty (cahgned cabel harnesses, checked grounds, new acomputers all around - probem ended up being soenoids in doors!!) I tried this first by cyclinc door locks, it did not perturb problem this time. Thanks so much. Mike
AnswerHi Mike,
The titles I find for 1698 say it is 'no ccd bus messages being received from the transmission control module (TCM)', not the ECM.
The only recommendation in the '98 body diagnostic manual is: to verify that the wires for the ccd bus from the transmission plug to the data link connector are patent. The + side is on pin 3 of the data link connector and - side is on pin 11 of that connector. At the tcm plug those pins are 43 and 4, respectively. If those prove out and neither side is grounded, then the remedy given is to replace the tcm. The only programming needed for a new tcm would be the pinion factor so as to get the correct vehicle speed and perform a 'quick learn procedure'.
All the symptoms you have are with devices/functions that are intermediated with the ccd, so if the error code is correct it would imply that the tcm is causing the problems with the ccd. The '96 cody manual has an alternative additional to the tcm replacement: the body computer replacement. The differentiation is done using the Chrysler DRB III reader, so that is something you might want to consider (e.g. a dealership).
If you are confident with the code reader's accuracy then check out the price of a tcm. Then compare to having a dealer do a readout with their DRB III is about all I can suggest. If you get a different code number let me know.
There are a couple of other possiblities to try:
If you have had rain or a car wash it may be the case that water leaked around the lower left corner of the windshield and gotten on the body computer and/or between the body computer and the fuse block. So try removing the plugs, and separatating the fuse block and body computer which are electrically connecting at the interface, and drying them out with some electronic circuit cleaner spray which will evaporate the water away.
The other thing to try is to remove each of the ccd bus-using modules, one at a time, to see if anything changes when you turn the key to "run" and then to "start". Start with the less importsnt: radio, compass module, instrument cluster, abs, HVAC, tcm, air bag. Disconnecting the bcm will probably cause issues if disconnected as would the pcm but maybe one of those other modules is bad and causing the system as a whole to fail.
Roland
PS Please let me know if anything works for you. Use the "thank/rate" tab below to get back without having to wait for me to be 'available'. There is a space for comments.
I brought Van into Dodge as I spent almost 2 eves trying to analyze and come up with a definitive way to attack the problem. I read all TSBs, Recalls, etc. After 1.5 days Dodge mechanic found it to be a burned out ASB Module on underneath of VAN. BUT, he found it only after taking out every other compputer first (ECM, TCM, BCM), took aapart dash, door panels, door locks, overhead display (compass, etc), side panels. I saw the Van all apart myself. Total cost to repair is $2200 - Per Dodge, the ASB module itself is $1100 + $300 harness. Van only worth about 2-2,500, but getting another vehicle is much more than the repair. So basically caught between a rock and a hard place. I looked around for ASB module prices and they ranged from $300-400. So Dodge simply marks them up about 300% !! Oh Well. Thanks to guidance provided in this forum - I hope what I learned (and will pay) will help others.
Mike
Hi Mike,
Thanks for the update. It is worth knowing that even though the code that came up was for the tcm that it was actually the ABS module that was bad. Going each of the ccd devices was the way to find it. I wonder if you might get away with just letting the ABS die and not replace it at all? Supposedly the brakes will work the same as if you never had ABS in the van. If money is an issue that is worth considering.
Roland
