Does anybody know anything about automatic transmissons? My D4 light comes on no matter what gear I am in. I then have to shift and I have no over drive. I tried replacing the solenoids and changing the fluid. And it is still having problems.

 

have you tried to jumper the service connector to see if there are any codes stored?
You might have a bad TCU, sometimes you can open them up and find fried components, or leaky caps.