Wiring diagram for JA1T-14G229-AJ

I bought a TCU from a wrecked 2018 MKX and I’m trying to install it into my 2016 Fusion, long story short every time I connect it to the HS3 CAN line everything on that line cuts out and Forscan shows nothing on HS3. I have read that some TCU’s aren’t compatible with HS3 and use I-CAN or HS4. Would like to know if I’m wiring this up right or if it doesn’t support HS3?

HS3 is the same as ICAN. If it is a K series TCU than it runs on HS4 and would not work.

I believe the JA series is an HS3 TCU and it would not affect the Canbus if it was plugged into it. It just would not work until the AB are corrected. Pretty sure an 18 MKX and 16 Fusion are CGEA 1.3 and no HS4.

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was odd, i just used testing pins and connected them into the acm connector and as soon as both hs3 high and low were connected my ipc shuts down and doesnt respond till i disconnect the test pins

is there another location I can connect my test pins to in order to possibly get it to show up and not mess with my hs3 can line, my fusion isn’t equipped with a DSP and I’m unsure if my model even has the harness to support the DSP

Also curious if US TCU’s are compatible for use in Canada. If this TCU becomes a bust then I’ll start looking for another one

Don’t connect stuff while your system is on. You need to have your car turned off when you do this. If you don’t the GWM will shut everything down on that Bus. I belive the NA TCU’s work in Canada but I am not 100%. I know the EU ones will not work in NA. That would not affect your Canbus issues though.

Not sure what pins your using on the APIM but here is the Pin diagram. I also put the ACM pins in case you find it easier to use those… Make sure you have the polarity right also or it will shut the buss down.


tried it even with the car completely shut down, only the hs3 can line shut down so clearly i was on the right line
when trying from the car being off, nothing on that line comes on

This is definitely shorting the HS3-CANBUS. You should be using pins 8 (+) and 16 (-) from the TCU to a connection point on the HS3-CAN network in the vehicle. This connection must be in parallel with the existing network, you cannot disconnect a module and substitute the TCU.

Some earlier Ford CGEA 1.3 vehicles have a test port available near the GWM connection under the driver’s dash area. It is a 4-pin connector. It contains a breakout for HS3.

I’m not sure my 2016 fusion has this test port, would you happen to know if it does at all?

You would have to look for it or find the appropriate diagrams.

Alright I’ll go take a look here in a bit

So I don’t have a test port on my car but I’m wondering if the remote start/perimeter alarm (installed myself with a ford ordered kit) can be tapped into, it t’s off the smart datalink (OBD) connector, if not where should I tap into. My car isn’t equipped with the Sony DSP and I’m not sure if the harness is there to connect to.

The DLC does not contain the HS3-CANBUS, only HS-CAN and HS2-CAN.

Make sense, I’ll have to look to see if my car has the DSP connector and tap into that line

Where do you recommend I buy a PDF of my vehicles wiring diagrams

@bill32399 might have something…

Will wait for his reply

I don’t believe you will have the connector. It’s a totally different rear floor harness. But in case I am wrong here is the pinouts for the DSP connector.

I have to agree with @F150Chief though. What you’re describing when it shuts down is exactly what it is supposed to do when it is shorted out.



I do have a connector that looks super close to this right behind the passenger rear seat tucked in the trunk, curious if this is the connector that’s supposed to have the DSP harness

DSP has 2 plugs. I sent the module locations for you also.

The only connector I know of back in that area is the rear heated seat connector for Lincolns.