Pcm: U0073, ic: U0019, eps: U1900, rke: U1900
 

Ok guys I usually spend a lot of time doing my own self diagnosing issues but this one baffles me. I've done some searching and have found threads with these various codes but no one seems to have posted what their solution was. Ok so here is whats going down and if anyone can point me in the right direction it would be greatly appreciated.

Ok some starter info, 04 GT roughly 55k miles, various mods, car runs great minus the oil leak from the oil pan and OMP that I haven't gotten around to fixing yet. Leak doesn't appear to be coming from front seal, will know for sure when I reseal the OMP and oil pan later next week.

I noticed a few weeks ago driving to work that sometime during my drive the TCS/DSC indicator light came on and stayed on doing just my usual daily driving to work. Get to work, turn the car off, get out of work turn the car on light is off so I'm thinking ok, fluke incident no big deal. The car drove like normal.

Now I've noticed it happen a couple more times and finally tonight I realized that this wasn't going to be an isolated incident. Once again it is just the light that comes on, no ABS light, not the DSC off light, just the TCS/DSC light. Car drove like normal, no loss of power to the wheels. It didn't come on until I was almost home. So I grabbed my AP and tried to pull some codes and this is what I've got:

PCM: U0073,
IC: U0019, (what system is this?)
EPS: U1900,
RKE: U1900 (what system is this?)

Searching didn't provide much info, workshop manual points me toward the multiplex communication system. Going through the flow chart it gets me to narrow down CAN system malfunction location, which is of no help to me.

Once again, it doesn't feel like the car is effected in any way, the traction control might not work, not sure didn't try to force it to kick on. I'm sure when I go to drive it tomorrow it will be off again and might not come back on so it is a intermittent issue.

Anyone else run into this issue, dirty/bad electrical harness somewhere? I do live on a dirt road but it's a short dirt road and most of my driving is on pavement. Mechanical probs don't scare me, pulling an engine doesn't scare me. Electrical issues on the other hand do scare me, I have trouble grasping what I can't see, I can't visually see electrical currents, I've even read through HPBooks Custom auto wiring and electrical and I still just don't have a good grasp on electrical systems.

Any tips, help, flames would be welcome.

Okay so I reset my codes before going to work today, now I have a P0000 code and none of the others have come back yet. I've searched and the P0000 code isn't even listed in the DTC code list WTF?

Frustrated, I would like to figure out what is going on before it becomes a constant problems.

Those are all CanBus communication errors......what are you using to read the codes?

I have an accessport, so does that basically just point to a communication error in the DSC system with nothing more specific? It sort of sucks that the problem comes and goes because without it staying on I have no idea if any trouble shooting things I try will actually fix the problem.

If you have no functional problems....reset the ECU and ignore them :)

Wait a second, doesn't a can bus communication error have to do with the OBD port and the pcm? So how would that effect my DSC or is it tied into the same system? Like I said electrical systems confuse me, it might help to add that I did have the connections on my OBD port repaired because my accessport was having a hard time staying connected but since then I've had no issues, my accessport is always connected when I drive.

Note: Since having the connections repaired I no longer unplug my accessport cable from the OBD port, I rerouted it so my accessport cable stays connected and my accessport mounts on one of my center air vents via phone clip.

Will do, it just sort of freaks me out when my traction control light comes on and I'm not driving like a bat out of hell. Mabe I'm worrying for nothing, I do tend to do that, she is my baby after all.

I would do some connection maintenance with a can of contact cleaner......I would pull the plug for the ABS pump...and do the ecu connections as well....As well as check the grounds in the engine compartment

Will do and thanks for the help, I have four days off in a row comming up and was planning on fixing my oil leak, removing my air pump, and now I'll add electrical harness cleaning to my list.

Rke is your keyless enty system

Forgot what ic was right now.

It means your pcm is not commicating with the said modules correctly, i would check the wiring and see if there are any shorts on it. But that will be a pretty painful thing to test ...

All of those stuff can be found at the passenger side of the car(right side)

Oh, i just remember something.

Check the connectors by the wheel that goes to the front abs sensors. I had one of them came loose on me once and it triggered everything including the dsc ligths and stuff. Clean and replug, never happen again

And an intermediate short on the abs/wheel sensor will trigger dsc malfunctional light, u might want to check the sensor wiring with an multimeter, just connect both pins and move the wires around, if the numbers jump or beeps then u know whats wrong

Keyless entry system, hmm thats weird, never had a problem with it at all. Needle in a hay stack more or less, guess I should start from the ECU and work in? Am I mistaken or is the ECU the same thing as the PCM? I'm wondering if mabe some of those codes had been there from my OBD port issues and I just never checked to clear them.

I know exactly what connectors you are refering too. Looks like I will finally have to chance to use my super nice simpson milliammeter that my father in law gave me.

Oh well, at least it gives me something to do while I'm waiting for silicone to dry.

Update: I cleaned the wheel sensors as well as most every electrical harness I could get my hands on and no more electrical issues. I pulled appart the wheel sensors and they where full of sand. I love easy fixes :ylsuper:

Bump-
Can you be a little more detail on how you removed and cleaned the front wheel sensors?

My dsc/TC no longer work and I get the code esp u1900.

Thanks

most issue came from the Front left wheel

just remove the cover that covers the oil cooler and u'll see the connectors, remove it, spray contact cleaner the shit out of it, let it dry, reconnect.

Another issue I have seen is that when ABS pump fails, it can give u this error as well.

My abs functions. Just one rainy day my DSC stopped working. Later that day it worked for like 3mins? Then never again. I'll check the connectors again tomorrow. I already went through most of the list on here https://www.rx8club.com/series-i-tro...taying-202843/ #13 is the only one I have not done.

I done a lot of digging in the FSM, and online over time. The code I get is "ESP U1900" which really only states there is a CAN bus communication with a device. I would assume the DSC module is having trouble talking to the Electric power steering module.

This morning I removed the ECU/ESP/NoiseFilter and cleaned all those connections with no results. Power steering feels the same...

I really don't think it's a wheel sensor. I had a rear one fail, and lost ABS till I replaced it. I just read he had cleaned it, and thought it couldn't hurt to try.

DSC/TC is usually the first thing I turn off when I start the car, so it's never been a real priority to fix. It's just that damn flashing light drives me crazy. lol

it function somtimes even the light is on

u can try to do that first and see what happens.

wheel sensors wouldn't throw a U code, it is specific to the bus system between all the modules. basically it means there is a breakdown of communication between the various modules that have the error.

in most cases the errors come up when connecting a scanner with the key in the already on position which can set any number of U codes to pop up if the scanner interrupts the communications in process.

if not the above cause usually U codes are simple connectivity issues at the control modules themselves, but it could run deeper into a harness issue where the bus wires have been frayed and contacting ground, interrupting communications.

wow great work on the “hard wire” I’m having the same issue but like like worse. I trusted the go behind the counter of AutoZone sold me a rad cap and the camera with brand, but it wasn’t sheeety ended up getting some coolant under the hood on the freeway and I believe it caused a pretty good amount of humidity under the hood.
https://cimg3.ibsrv.net/gimg/www.rx8...94b5a5217.jpeg
https://cimg4.ibsrv.net/gimg/www.rx8...85e818545.jpeg
https://cimg5.ibsrv.net/gimg/www.rx8...a3df36423.jpeg
https://cimg6.ibsrv.net/gimg/www.rx8...f95cf79cf.jpeg
https://cimg7.ibsrv.net/gimg/www.rx8...d68c036f5.jpeg
https://cimg0.ibsrv.net/gimg/www.rx8...20858ec3b.jpeg
https://cimg2.ibsrv.net/gimg/www.rx8...9d0bec1d2.jpeg
forgot to mention it decided to rain tonight I guess my question is is I can’t give her my attention you gotta be working like four hours and I just left her home. Do you think it’d be a good idea to disconnect the battery until I can resolve this within the next day or two.
i’m only tripping because I have a same issue with OBD port. I have to kinda like put upwards pressure on it plus all the moisture today. I’m not really sure what it is because I have already cleaned and greased good amount of connections

ARe you sure the coolant bottle neck, where the rad cap sits, isn't cracked?
You really need to start your own thread in the new members section. It's hard to keep up when your problems are in many different threads.