Will not shift

Tiny
MNATV
  • MEMBER
  • 1994 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 117,000 MILES
My transmission shifts from first to second when the van is first started and stays in second from there on and the speedo also does not work. The codes come up with a 15 code for the speed sensor. I have replaced the two sensors at the top of the transmission but am still having the same problem. I have checked the wiring to the computer from the speed sensor and it all checks out. There are two other sensors down buy the trans. Pan (I do not know what there for) and while I was tasting the wiring to to speed sensor I unplugged them as well. I put everything back together after cleaning all connections. Then I took a test drive and the speedo would try to work under braking but the trans. Still did not respond. Could one of the other two sensor by the trans. Pan be the problem if not what are try for?
Friday, February 20th, 2009 AT 6:55 PM

6 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Do these sensors look almost exactly alike? If they do they are the input speed sensor and output speed sensors and are very common for failing causing your problem. I would not hesitate to replace both of them. Make sure you put the new ones in the right spots. Also check the wiring harness for chafe marks in it, they also have chafing problems on the bottom of the trans pan where the harness runs near it
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Friday, February 20th, 2009 AT 8:44 PM
Tiny
MNATV
  • MEMBER
  • 2 POSTS
Just getting back to the Caravan and I see that your response tells me to do exactly what I already did (please read my initial question thoroughly). I replaced both speed sencores and I checked the wiring to the computer. I looked into the sencors by the pan and they are the nutral safety switches which are working. Where should I go from hear?
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Thursday, April 2nd, 2009 AT 1:20 PM
Tiny
DANGINA
  • MEMBER
  • 3 POSTS
Mnatv we seem to be having the same problem with our van could you pm us when you get some answers. We are new and this is our first post
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Monday, April 6th, 2009 AT 5:56 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Check the wires from the output speed sensor from the transmission to the transmission control module which is in the left side of the dash


http://www.2carpros.com/forum/automotive_pictures/139033_coil_11.jpg

the wire colors are dark blue and black and the other wire is light green and white.
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Tuesday, April 7th, 2009 AT 6:43 AM
Tiny
MNATV
  • MEMBER
  • 2 POSTS
Mastertechtim thank you for your help. The wire color was the clincher. The three sensors I had originally changed did not have those color wires connected to them. When I found the wires I fallowed them to the speed sensor I did not replace and when I replaced it the problem was solved.

Thanks again,
MNATV
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Wednesday, July 1st, 2009 AT 8:48 PM
Tiny
CHRISGARRETT002
  • MEMBER
  • 1 POST
Can you tell me it your sifting problem was consistent? I have a similar problem, but the shifting is not consistent. Some times usually when the car is cold it shifts without a problem. Other times usually but not always when the car is hot, it will not shift at all. So I did the VSS and the problem went away I guess it was intermittent.
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Monday, July 6th, 2009 AT 10:51 PM

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