2002 Dodge Caravan transmission problem?

2002 DODGE CARAVAN
85,000 MILES • 6 CYL • FWD • AUTOMATIC
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The other day my speedomter, odometer and gear indicator stopped working. There are "boxes" around the PRND23, so I can't see what gear it is in. Now, today, when I was stopped at a light, the RPM's went down, and the van shut off. The speedometer, which hadn't been moving at all, went crazy just before it shut down. The van seems to pull back at times, as though it is in a lower gear. I did a self diagnosis test I read about on-line, and got the error codes saying "loopback failure", EATX communication fault" and "improper power down detected" What does all that mean? I know nothing about cars, and would like to have some idea what the problem is before taking it to a mechanic and possibly being ripped off. Thanks!!!
Aug 3, 2009 at 7:15 PM
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Improper shut down may be related to a battery issue. The cluster can have adverse reactions when the battery power is abruptly stopped.

What are the code Numbers?

The BCM is my first suspicion, but would like to know what code numbers are shown.
Aug 4, 2009 at 5:51 AM
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Code numbers are 100.0,100.3 and 400.1 What does BCM mean?
Aug 4, 2009 at 7:04 AM
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Bottom line with this is going to find a shop that is good at troubleshooting. A shop that specializes in this typically has a reputation at stake and works hard to solve it right the first time. It doesn't always go that way, but a good technican will seek to solve this as best as possible.

There are cluster problems with these and I think this is where this may be headed. There have a lot of problems with the circuit board connection to pins where the connector plugs in on the cluster. Many techs carefully resolder the connections to restore reliablity. This can also cause a "no Crank".
You can unplug the cluster and see if the van drives better. IF so, look at the cluster or replace it.

It may be a connection problem.
Connectors should be examined at the PCM (powertrain control module), BCM (Body Control Module) and Cluster.

Loopback Failure can be checked by clearing the codes with a scanner. Don't recommend pulling the battery cables off, as the voltage spike can cause damage. Turn the ignition on. cl;ear the codes, turn off the ignition for 15 seconds, turn back on and check for codes. Loopback failure returns, look at the cluster.
Aug 4, 2009 at 7:09 PM
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I went to autozone today and had them check why the check engine light was on. It said somrthing about the speed sensor. Could that be the whole problem? How do I "unplug the cluster"?Thanks for your help.
Aug 4, 2009 at 7:19 PM
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Need specifics on the trip to autozone. What is the code Number? Sounds like 2 different problems. But...


https://images.2carpros.com/forum/automotive_pictures/30961_caravan_cluster_rra_1.jpg


https://images.2carpros.com/forum/automotive_pictures/30961_caravan_cluster_rr_1.jpg

Aug 4, 2009 at 7:33 PM
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There were several codes. Some have been there for awhile and I have been told it's my gas cap that keeps setting it off. Here are all the codes, not sure which one was the speed sensor one- 500,1698,442,455 & 456. You mentioned clearing the codes in regards to the loopback failure, how do I clear them?
Aug 4, 2009 at 8:04 PM
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PO500 is the speed sensor.
Possible causes are wiring problems, defective PCM, Defective TCM, TCM codes,

p1698 is no bus messege from transmission control module (TCM).
This code pushes me more toward the cluster's solder problem as it is a link for communication.


The other 3 are the evap leaks. Buy a gas cap to see if it clears them.

Codes need to be cleared with a scanner. Disconnecting the battery will cause a voltage spike and can cause problems, but will also clear the codes.
Aug 5, 2009 at 5:25 AM
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Thanks so much for your help!!! I feel better being "armed" with knowledge about the possible issues. I'll keep you posted.
Aug 5, 2009 at 8:08 AM
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