I have tried pulling the cluster out to see if it was that, but no dice. I will try again for good measure. Good news though. I jumped the dlc and pcm (data lines wiring diagram shows a direct link between PCM and bcm) and scanner works while running. Haven' tried adding the other modules through the sp201 yet though

 

alright so what exactly in the splice pack is the brown white wire connected to I haven' tested the yellow wire yet but that Brown one disconnects my scanner. And my fuel gauge seems to bounce around while in park occasionally going empty with fuel light and other times full or just wobbling between two quarter marks
Edit the fuel gauge happens with the (pcm bcm and cluster jumped) and only in park
Edit 2. The fuel gauge throws code P0463 fuel level sensor circuit high input

 

https://www.google.ca/search?q=2004+...=1524164079482

from the link above that I included in post #16.

Brown/white is to memory seat module driver. Yellow is to the driver's info center. Is the memory seat module driver or data wire pulling down the entire serial data line? Jumpering terminals A and B should be all that you need in order to connect with the PCM. Of course its going to set different codes in the process and make things act whacky. Idea I have is to then add different systems back in at SP201 until you get a malfunction with the OBD2 connection. That way you presumably wouldn't need a Tech2 to test communication with each module.

Not exactly sure what you are jumpering at SP201, how you are disconnecting wires at SP201, and if you have removed the splice pack from the connector........

But if the brown/white wire kills your OBD2 connection somehow..... Try checking the wiring under your driver's seat - specifically the brown/white wire - if nothing found then disconnect the memory seat module and hook the rest back up at SP201 and see what happens. Without the Tech 2, you have to invent a roundabout way to functionally test the same thing.

I really think you are close to finding your problem. Cars can be pretty weird.

Once had a bad tail light bulb and a blown fuse make intermittent wipers take a single swipe across the windshield when the brake was applied.

Once had a bad alternator kill the engine as soon as it started and began to charge. Just like you shut the key off. Overcharge freaked out the computer and it shut down for protection.

Once had a bad starter solenoid kill the engine when put in drive, but not when put in reverse or into neutral. This solenoid was 70's GM that had the wire to the coil that energized 12V during starting and solenoid would rock back when put in drive and short out.

And all this was way before serial data lines, modules, and intra-vehicle networks....

 

thank you. I don' have power seats so I just cut that ****er for now. The fuel gauge if left sitting in idle at park will stay at empty and will not work until I clear that code. Power windows still only work with master controls, but that probably has to do with code b3137. Car still dpesnt auto lock doors above certain speed nor with remote or remote programming mode. But atleast i have my damn cluster again

 

Ding ding ding!!!! Good Job!!! Looks like these other problems are probably separate issues. Cluster still might be bad for the fuel gauge, but you can treat as a separate issue now (as you can the power windows and auto door locking). Good luck. Let us know if/when you want to do something with them.

Just to wind things up.......in review....... Problem was that the serial data line to the memory seat module (that your vehicle doesn't use) was somehow grounded, pulling the entire serial data line down and causing all kinds of electrical gremlins to appear in your instrument cluster along with U series codes for serial data problems and difficulty connecting to a scanner. Diagnostic was to find what serial data line caused the scanner to not connect with the PCM by isolating the diferent circuits at SP201. Cure was to disconnect offending serial data wire at SP201, as it was unused. I love it when things actually work out!

You're a smart kid! (I only call you a kid because I'm an old fart).