Questions and Answers
Grand Caravan Shifting Problem
Q. I have an 1989 Dodge Grand Caravan, 3.0 liter Engine, Automatic, A/C, all the usual stuff and about 150,000 miles. Engine rebuilt as well as the transmission.
The problem I'm having is the transmission going into Safe mode. I've had a test unit attached and they say loss of power. I've replaced the Safety Shutdown relay and the Transmission computer. Recently I got a schematic of the system and realize that the shut down relay is controlled by the Computer. With various LED's attached I've monitored power and a couple of other inputs, all seem ok.
Now the symptoms are: in the winter no problem. Now that it's getting warm the problem comes back.
Let the engine Idle until hot (up to temp), then start to drive away, the Safety relay will drop out. I've heard that there were early versions of the Transmission Computer that can cause this, but, I'm also wondering if it could be the type of oil. I've had the car back to be checked a number of times and been told each time there is nothing wrong , all pressures etc ok.
Any suggestions would be appreciated.
A. Chrysler had a couple of electrical gremlins creep into the transmission electrical system. One is a faulty computer ground and the other is damaged connectors.
Using your wiring diagram, locate the ground wire and make sure the connection to the body is clean and tight. Chrysler recommends adding a second ground wire as well to correct the problem. Just cut and splice a second wire into the original ground wire and run it to another grounding point on the body. Make sure you remove any paint there may be at the attaching point.
This condition can also be caused by poor electrical connections to any of the input/output devices used by the controller. Make sure all of the connections are tight and there are no bent terminals in the connectors.
Chrysler has two repair kits available in the event that the harness connector for the speed sensors or solenoid assembly are damaged.
Additional Information provided courtesy of ALLDATA
