Hi all,
Can anyone here point me where to look next to solve this problem? I apologize for the length of the post, but figure the information is necessary for a reasonable diagnosis. I bought an Alldatadiy subscription for the car, so I have the wiring diagrams, but I don't have a lot of money to spend on parts or dealer DRB work. Any help is greatly appreciated. Here is the story:

1998 Dodge Grand Caravan 3.8 w/ 4-spd electronic trans 175,000 miles Series NS

Purchased car in following condition:

Transmission in Limp Mode - only forward gear is second.
All gear ranges on dash gear selector indicator are boxed and lit.
Speedometer does not move (motionless at 120 mph).
Check engine light on: Codes P0500 (no vehicle speed sensor signal) and P1698 (no CCD messages from TCM)

Performed this work:

Used (85K) transmission installed with new seals, filter, input and output speed sensors.
Instrument panel connector pins (13) on circuit board re-soldered. Speedometer needle moved by tilting cluster to return needle to zero.
Connectors at TCM and PCM checked for corrosion, dirt and damage; dielectric grease applied.
Wire harness under battery checked for corrosion. Outer covering discolored but no evidence of corrosion damage.
Body ground under battery cleaned and dielectric greased.
Installed rebuilt TCM programmed with VIN and mileage

Current conditions:

Transmission in Limp Mode - only forward gear is second.
All gear ranges on dash gear selector indicator are boxed and lit. (Alldata possible cause: no CCD bus message from TCM)
Car starts, runs and drives in second gear; repeatedly sets code P1698 “no CCD messages from TCM.” Same conditions with TCM installed or removed from car.
Speedometer needle does not move. Remains motionless at zero.

Test results:

CCD + and - wiring between PCM and TCM tests less than 1.5 ohms
CCD (+) and (-) at DLC read about 2.5 Volts with engine running.
TCM ignition feed (pin 11 – R/W) reads 12 Volts in both start and run
TCM igntion feed (pin 8 – Y/R) reads 12V only during start
TCM ground (pin 53 – Bk/Y) is continuous to battery ground
Wiring between TCM and speed sensors tests less than 1.5 ohms.
TCM sensor ground (pin 51) is not continuous to body ground or battery ground.
Instrument cluster test returns code 905 “no CCD bus messages from TCM”
Speedometer calibration test moves needle to 0 – 20 – 55 – 75 mph.

I was thinking I would take a look at the wiring between the TCM and the BCM next...

Any other ideas?

 

if i where you id first try to unhook the batt and hold the pos and neg on eachother for atlest 2 min to reset the systems and if that dont work go to a junk yard and try to find a matching numbers TCM because iv seen a simaler problum that swaping the fried TCM took care of
hope this helps

 

Thanks for the reply, Jenson. I have cleared the code (p1698) and replaced the TCM with a known good unit. Symptoms are exactly as before!

 

The code means the PCM is not seeing messages from the TCM. If both of the bus wires are ok between the PCM and TCM (ohm them for opens, shorts to ground and to power), you need to see if you can access the TCM with a scan tool, if you can, the PCM is probably faulty.

 

Thanks for the reply, Tizzy. What sort of scan tool would I need to access the TCM? I have an OBDII code reader; I'm thinkin' it won't do it.

 

.....

 

Some will and some won't. Try to read the codes from the TCM, if it reads the codes, it can talk to the module and that's all you need to know is if communication is possible.

 

Well, I will clearly need to get something more sophisticated than my tool. It will only read P codes.

 

try replacing the ignition switch.

 

Thanks, Master Tech, for the reply. I was double-checking things last night and discovered that the voltage on the CCD - wire (Wh/Bk) is positive 2.5 volts instead of negative. Voltage on the CCD + wire (V/Br) is also positive 2.5 volts. I reversed the leads on the meter (black on wire, red on ground) to make sure the meter would read negative voltage, and it did. I am wondering if this could this indicate a bad module somewhere in the CCD system?