Jeep KJ Transmission Monitor

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Jeep Explorer

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I have written an Android App for my Jeep KJ 3.7 with PCI Bus in the last 12 months.
This App shows the status of the 42RLE transmission. After a few test drives it seems to work well.
I have uploaded a video to YouTube which is showing such a test drive, more details and a description.
YouTube link: https://youtu.be/VkV3i33ccdk
The App is using an ELM327 bluetooth adapter.
If you have an ELM327 bluetooth adapter you can also download a test version of my App from here.
Note!
Some of those cheap Bluetooth OBDII adapters do not support all ELM AT commands (ATAL, ATPPS, ATPP, ATE0, ATMA)
and the App KJ Trans Monitor reports a syntax error.
The J1850 PWM and J1850 VPW pins 2 and 10 of the OBD plug are often not connected. Only the ISO9141 and CAN pins
are connected. This will not support any of the J1850 protocols.
Because the Jeep KJ (with PCI Bus) uses the J1850 VPW protocol the connection fails.
 

Jeep Explorer

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My app has been tested only with the NGC controller with integrated TCM (Transmission Control Module) -> Transmission: 42RLE. 2002 and early 2003 models works with the older JTEC controller and use a separate TCM -> Transmission: 45RFE .
I don't know whether the PCI bus messages of the JTEC controller match those of the NGC controller. Therefore I can not answer your question.
 

uss2defiant

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Is there something I can do to help with getting a version of the 45rfe to work?

I could not even connect to my Bluetooth obd2 with the PC based software.

From your first post it sounds like those cheap readers won't work?
 

Jeep Explorer

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Not all of those cheap readers won't work. Especially the older cheap readers (USB and the first Bluetooth) work perfectly.
I have ten ELM327 clones. The readers which I bought about three to four years ago all work well. The newer ones all fail.
Take a look at this link: Inside a fake ELM 327 – fadvisor.net/blog
In the end I have bought a reader with an original ELM327 chip. To test whether the reader is able to work with the J1850 protocol you can try to connect via the App Torque or a Terminal-Programm.
Take a look at this link: https://theksmith.com/software/hack-vehicle-bus-cheap-easy-part-1/
To check the bus of your Jeep you have to create a text file which contains all the PCI messages as described in the link above. Based on this text file I can tell you whether the app works with the transmission 45RFE.
 

nbas

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Hello Jeep Explorer! First of all I would like to congratulate you for your work. It is something which was needed from many KJ owners!
I have downloaded your Android App and tried it. It connected to the elm327, and I get all information except transmission temperature.
I bought the elm327 with the original chip, as another cheap clone I have, does not connect to the ECU.
Do you have any suggestions on what might be the issue?
 

nbas

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Does anybody know how we can find the VIN UnlockCode?
I do not have it nor know where to find it, and this is why the transmission temp won't show...
 

Myke

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Anyone have a link to download the app created by the OP?
 

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