Tcu wont be read in vehicle network

Good evening/morning guys, im officially stumped. I have a 2020 transit connect, i recently did an apim swap for one with nav, everything works however i found now that my tcu isnt coming up in forscan, the vehicke initally came with a K series non nav apim and i swapped for a J series apim with the latests maps and 3.4 version installed thanks to the team at cyan labs.

From what i gathered my tcu is on the hs4 network and its the only thing on the network. I tried enabling hs4 on the apim, modules resets, master rest of the apim and even pulled the battery and let it reset everything.

I cant really verify if its due to the apim being of a older vintage or the tcu being newer.

Looking for any wisdom in the community of anyone having this issue or possibly a fix.

J apim with nav
K tcu with both the purple and white plugs in use
2020 transit connect xlt

I get code U0198-87 in the bcmii lost connection with the tcu/missing messages

When i try and pull the onboard modem number its blank and wont populate

TCU is expecting communication on the HS4 bus.
The J series APIM only has HS3.

I came to that realization at the end of my shift this morning lol. But thank you for your insight. Would a K apim work better? Im scouting one thats nav starting with KC3T

Theres a ton of L apims but i like being able to update it

APIMs are agnostic since the config loaded into them can vary among models/years based on the trim and option package of the car. The odds of getting one that’s a simple drop in are small unless its a same model/year/trim/option donor.
In your case you’ll still need to drop you factory AsBuilt into the new unit followed by flipping the bit on the APIM to enable NAV (as your factory unit didn’t have it).

With Ford’s part numbering, J is a part first introduced in 2018/K is 2019/L is 2020 etc, the reset of the first group is the model (eg JS7T is a 2018 Fusion, KS7T is a 2019 Fusion) the next 2 digits are the part number group, the last 3 the vendor, the final are any deltas in the part, this could be as simple the mounting bracket it ships with, firmware/calibration loaded. So to use a Fusion as an example, an APIM with a part number of KS7T-14G370-BBG is a non-nav APIM while a KS7T-14G370-BCH is a NAV unit.

The problem you may run into using a K/2019 is that the firmware in it may not be fully compatible with the other modules in the car and as a few folks have found out the physical hardware change in the APIM for 2020 started in 2019 and there are no reliable external markings on the APIM that guarantee that you’ll be able to reformat it without going the FMods route.

What an amazing write up. Thank you so much for taking the time to put this out here. I can PM you my vin if you need or any other information that could help me.

As far as i know of the donor vehicle its from a 19 F250 lariat and the apim has a build date of october 19.

Ill try and source one from another transit connect of my year with a K series with nav but as you can imagine between the cheap chinese knock offs and the plethera of H/G/J on the used market.

I at least have this site to try and run the part number to see if it has nav at least so that helps. But my search continues.

I fully expect that you’ll need a 2020MY+ APIM.
I’ve never heard of a FACTORY installed Sync3 APIM which supported HS4 that wasn’t a 2020MY due to the firmware/calibration (and possibly not having a internal trace connecting the HS4 pins to anything).

If I’m wrong someone feel free to correct me.

A K series APIM might work. The later K series TCU were HS4 so there is a good chance the K series APIM is HS4 capable.

Well i can say with confidence the one that came out of it was a 4U5T. Which is a K and it had a production date of 2019 as well. The car is a 2020 year model but was built end of 2019 sept/oct if i remembered right.

This is where the interrogator/ForScan comes in, you get the actual hardware identifier.
The label doesn’t guarantee that the unit is 2019 hardware vs 2020 hardware.
We had folks that had units with 2019 4U5T on them that were 2020 hardware. The unit I currently have in my 2018 Fusion came from a 2020 F150 with the APIM having a 02/2020 date and its not MY2020 hardware.

As Bill said some 2019s were HS4 with the 2020MY spin up, so maybe a 2019 Fusion since Ford used those as somewhat of a guinea pig model. I’ve pulled TCUs from those with K part numbers and J firmware, so maybe an APIM from a Fusion with a DEC 2019 production date?

I just went through Oasis and a 2019 Transit Connect had HS4. This would be a K series vehicle and would have had it from the start of production. I still say try the K series you have first.

I checked my K series from 4/19 and it has HS4 when I use the L series GWM I have along with the L series TCU I have. Forscan shows it active when I enable it.

Sorry for the late response i was away this weekend. Ill heed both your advice. Ill try and find a K series with a late production date and from a vehicke that had HS4 in late 2019. Thhank you @warlock12118 and @bill32399

PS lol @bill32399 my explorer has a J series ive told you this lol.

My bad, Sorry. I thought it was K.

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