Vehicle: 2001 Dodge Caravan 3.3

I am pleased to declare this day a success! I first experienced error codes P1684 and P0700 last summer and reading these posts I learned the key on off trick to clear the codes and continue driving the next 4 months without problems and happy I didn't have to spend money at a garage.

Now to December and January my battery was no longer keeping a charge so that had to be replaced and error codes P1684 and P0700 kept coming back to the point that the key method would not reset and I was stuck in limp mode for a few days. Back to reading these posts again I went to Canadian Tire and bought an Input Speed Sensor for about $30. Many online diagrams can be seen to know where the Input and Output Speed Sensors are located. I used this one https://www.2carpros.com/forum/autom...ranny_05_6.jpg and zoomed in to see it bigger for clarity. Youtube videos where also helpful to see where these parts are on the vehicle if you're not an experienced mechanic.

At first I removed the Output Speed Sensor by mistake because it was the first one I saw. I used a small flathead screwdriver to removed the wire clip from the sensor and a 1 inch (or adjustable) wrench to remove the sensor. Though I did not have a replacement for this sensor I noticed very tiny magnetized filings attached to the end of the sensor which could potentially be a problem for this component. I simply wiped the particles off with a cloth and re-installed this sensor.

To buy the Input Speed Sensor for about $30 I used Canadian Tire money which is actually free from buying gas and other purchases using their card (not credit card but you can do that too). To remove this sensor I found a 1 inch socket fit nicely under the 2 black tubes above the sensor location so it wasn't hard to replace.

I just did 5 successful start/drive/shut off tests, the transmission shifted properly and no more code 0700.

BIG THANK YOU to everyone who posted useful information here and other posts to help with this problem! This could have been a much more expensive repair to pay at a garage and I would never have known without other people's posts.

 

Very Important Update to my previous post...

Cleaning and replacing speed sensors was not enough. Next day after I declared success was back in limp mode with P0700

Back to research, reading online, pricing parts and deciding what to do. The most knowledgeable person I know in dealing with Caravans is the guy I bought it from. Over the phone he suggested it could be the sensors, a solenoid pack, the TCM, or bad wiring / connections, all of which I knew about from researching online but I was tired of guessing what it could be and I didn't want to waste money and time replacing parts unnecessarily. He offered to diagnose it free with his scan tool so I would have specific detail of what is wrong. Great!

Even if I had to replace all parts mentioned would still be worthwhile for me to save this van.
$30 Input Speed Sensor
$65 Output Speed Sensor
$60 Transmission Control Solenoid Pack
$150 Transmission Control Module (Used) or
$450+ Transmission Control Module (Refurbished from dealership)

Compared to cost of new transmission or buying a new van, these parts and my time would be $ saved IF my repairs are successful.

Confirming most experienced comments I've read online the scan tool revealed the most likely cause in this case with P0700 was the TCM. I was able to buy a used TCM from a local scrap yard for less than $150 total. Without even removing the old TCM I simply unbolted the wire harness from the old one and fastened it to the new one, nestled the new TCM inside the fender and went for a slow test ride. All good! Shifted through the gears like normal and again no P07000.

All in cost of parts was less than $200 so I'm pretty happy I didn't need a full tranny job or replace the van just yet. Thanks again for information everyone has shared and feel free to ask questions if there's any more help I can provide.

 

Thank you, a junkyard $48 TCM fix mine too, after expending more money on sensors, solenoids, filter, gaskets. I drive a 2001 Caravan, the part came out of a 2002. Thank you video

 

I need one for 2001 3.3l caravan

 

That member was banned June 2010. Your best bet is to go aftermarket. Then you need to have it program too.