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Glenn, Technician/Trainer
Category: Dodge
Satisfied Customers: 606
Experience:  28 years experience, Interprovincially Licenced Motor Vehicle Mechanic and Trainer
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I have a 1999 dodge caravan 3.0l automatic transmission last

Customer Question

I have a 1999 dodge caravan 3.0l automatic transmission last night the speedometer stopped working and the transmission will not shift it stays in what seems like first gear. any ideas this gave no warning signs except the check engine light came on
Submitted: 9 years ago.
Category: Dodge
Expert:  Glenn replied 9 years ago.



My name is XXXXX XXXXX I'd like to try to help you with this problem.


Roadspeed information is gathered using the transmission output speed sensor. This information is processed by the transmission control module and then shared with the other components that need this information.


Ok, if the check engine light is on, it would be a good idea to read the powertrain codes. The transmission codes won't be available on a basic code reader... you'd need something that supports enhanced Chrysler diagnostics.


Do you intend to test this yourself? You'll need a digital volt/ohm meter to do the basic checks.


I'll put together some images and test points for you if you like.







Glenn and 4 other Dodge Specialists are ready to help you
Customer: replied 9 years ago.
yes I would like to do some tests myself is there any way to get the error code to appear on the odometer?
Expert:  Glenn replied 9 years ago.


Try cycling the key on, off, on, off, on and see if you get anything on the odometer...


This will only read the codes from the PCM , not the TCM.



Customer: replied 9 years ago.
I just tried it no info except the mileage
Expert:  Glenn replied 9 years ago.

That's ok...




Here's what the output speed sensor looks like. It's on the transmission.




I'd suggest you leave it alone for the moment. Sometimes disturbing a connection makes a problem temporarily go away. I'm going to suggest that we disconnect the TCM and measure the resistance of the circuit.







This is what the plug looks like.




Here's a partial list with an index of terminal numbers. I've circled the ones for the OUTPUT SPEED SENSOR (OSS for short from this point on, ok?)





I want you to measure the resistance between pins 13 and 14.


Is it showing an open circuit? What is the resistance?