Building a bench harness for GPEC based controllers.

[fumanchu182]

So I decided to build a bench harness for Dodge PCMs. I have all the free time in the world now that I have separated from the Navy and here is my adventure so far. Lets start with some components that I will be using. I decided to go with this power supply, it has 12V DC and comes with a terminal end, which will make it easy to work with: https://www.amazon.com/dp/B07C75RT38?psc=1&ref=ppx_yo2_dt_b_product_details. For the enclosure we are not doing anything fancy, only HomeDepot's finest will do. https://www.homedepot.com/p/BELL-We...ded-Outlets-White-2-Gang-PDB77550WH/316300308 topped off with a https://www.homedepot.com/p/Leviton...ker-Wall-Plate-1-Pack-R52-80409-00W/100048406 and two switches: https://www.homedepot.com/p/Leviton...t-Rocker-Switch-White-R62-05693-2WS/100162432. For the outside ground bus I choose the following from Autozone: https://www.autozone.com/miscellane...nduct-tite-black-universal-bus-bar/476883_0_0

So that's what will house all of the goodies. For OBD2 connector I chose: https://www.amazon.com/dp/B07F16HC12?psc=1&ref=ppx_yo2_dt_b_product_details. So here is an image of the internals and how this was all wired together:



Here is my reference for the DLC connectors and the IKKEGOL harness:


Here are a bunch of foundational images that I used during my sleuthing.
C1 pins and purposes:


C2 Pins and purposes:


DLC:



So with great pleasure I present the following:


The system powers on, I can then turn on the igntion switch and all the 5v power accessories turn on. Awesome, however I do not have good CAN +/-. It feels as if the car is in ACC mode only, which makes sense as I cannot connect to it with HP Tuners when the car is in that mode as well. For CAN- I read 2.224V which means the bus is in a dominant state (bus active) and for CAN+ I read 2.825 which is dominant. Not going into the nitty gritty of CAN theory but that's akin to throwing a bunch of zeros across the line and nothing else.

If anyone knows what pin would need power to put the PCM in run mode it would be appreciated. Also can someone explain ground vs sens ground in the wiring diagrams? I'm looking forward to getting this moving forward and any help is appreciated. This is all my research done on my own and help with my electrical partner in crime @Diboblo

 

[fumanchu182]

Here is my complete humble setup.

 

[Speedy!]

Cool project. Does the computer require some kind of security access to get past acc?

 

[fumanchu182]

Cool project. Does the computer require some kind of security access to get past acc?

Not that I am aware of, I am looking at all the hot at all time wires and seeing if I didn’t run power but it looks like 96 is the only hot pin. Tomorrow I will check every fuse before RUN mode and then see which ones activate when RUN mode is on and trace them to pins. Might be a trigger in the starter relay. Its been a minute since I have read electrical diagrams so the relays throw me for a loop.

 

[2fast4u]

^^ I have the Kess V2 and Ktag at home, I'll be back there after 5pm and look at what has to be powered to read it.

 

[Speedy!]

I "thought" the ECM was coded to the BCM in some way, and that those things were coded to the key fob that would allow the car to start. Been a while so I could be way off on it.

 

[2fast4u]

You can bench test ECM's with the right enables, only way I know of to unlock them,(opened on bench to access proper trace.)

 

[fumanchu182]

I "thought" the ECM was coded to the BCM in some way, and that those things were coded to the key fob that would allow the car to start. Been a while so I could be way off on it.

All PCM pins are simple in/out mechanisms for voltage. According to the FSM all the pins on C1/C2 are simple sensors. No data from the BMC other than LIN bus traffic occurs. (LIN bus is for mirrors, seats, etc). i Also checked all schematices to ensure that no CAN IHS connections were happening and that is the case. BCM can take all CAN and copy messages to CAN IHS if needed. My sneaking suspicion in this matter is that the CAN +/- go to this thing called a Star Connector, I'm noticing that in references all cables have 120ohm terminating resistors, which I don't have and are required by CANBUS specifications. Going to see if the local hardware store has any and solder some inline.

 

[2fast4u]

^^If you need resistors and can't find them, I have a pretty good selection of lab grade,(1%) at my house...will look thru the hundreds of test tubes I have them isolated in and see if any will do.

 

[fumanchu182]

^^If you need resistors and can't find them, I have a pretty good selection of lab grade,(1%) at my house...will look thru the hundreds of test tubes I have them isolated in and see if any will do.

Couldn't find them locally, put in an overnight order from Amazon, thank you for the offer though. Are you able to confirm my pins aren't dorked based on your KTag and Kess V2?

 

[2fast4u]

No, I was not...things came up and I didn't have opportunity. If I remember, there are 2 pins 1 full time 12v, 1 ignition 12v, plus ground and can H & L.

 

[fumanchu182]

I 100% goofed on this, was reading over some notes this morning while sipping on coffee and can confirm I need to create my own canbus and splice in or just buy a Star Connector, highlighted part is the important part, resistors are built in.



The Star connector can just be put in the box and made integral, so you can hook up as many connectors as you want. The resistors will be here today so I may just fabricobble my own.

 

[Speedy!]

What are you gonna use this for?

 

[fumanchu182]

Well now that the gloves are off and I’m not bound to the agency or the Navy I’m reverse engineering everything from our cars. A lot of information should be pushed out. The only things I wont publish are sercurity systems/immobilizers. I want to learn how to unlock PCMs and ultimately generate passive income streams.

 

[2fast4u]

@fumanchu182 ..check your PM

 

[BULL]

Well now that the gloves are off and I’m not bound to the agency or the Navy I’m reverse engineering everything from our cars. A lot of information should be pushed out. The only things I wont publish are sercurity systems/immobilizers. I want to learn how to unlock PCMs and ultimately generate passive income streams.

Subscribed

 

[coolblue]

^^^^What he said.

 

[Slows2k]

The CAN bus needs 2 terminating resistors, not sure what control unit they live in, or if they are part of the star connector.

 

[fumanchu182]

To bring it full circle did like @Slows2k said and created a temporary can network.


Then did my first read.

 

[Slows2k]

Next level will be if you make the CAN circuit wires pink and blue.