Car Won't Start / U0100 & P023F
 

My 2012 V6 won't start today. I've had some issues in the past with it doing some weird starting problems, such as "Service Anti Theft System" messages pop up, and last fall I had to replace my alternator due to it going out and preventing my car from starting.

Today I went out to start the car to go to the store and at 1st it was acting like a dead battery, the starter was clicking but no start. Tried to jump it and still nothing, just the starter clicking. So gave it a few to try and charge. But then on the 3rd attempt to start, the starter did nothing, no clicking, instead I got a message on my screen that said, "Service Stability Track".

So I hooked my laptop up to the car and scanned it with HPTuners and got the following codes

0x7EB: P023F - Fuel Pump Secondary Circuit / Open (Permanent)
0x7EB: U0100 - Lost Communication With ECM/PCM A (Pending, Current, Permanent)

I'm not sure if the P023F code is related to any of this or not. I will say I installed a ZL1 fuel pump back in 2016 though.

As for the U0100 code, I looked in some other forums talking about that code. I tried some of their solutions and still nothing.

May be a bad battery. Check the voltage.

Just put a battery in it less than a month ago. Although the car was only reading between 12.2-12.8 volts during all of this, according to the screen.

Could be a grounding issue. See if the engine ground strap is still okay.

Are you referring to the short cable going from the passenger side of the engine to the bracket that holds the abs?

So I just took a multi meter and poked around the car a bit. I was getting 13 volts directly from the battery terminals. I was also getting the same reading from the positive terminal in the engine bay and any place I used for ground. Also got 13v at the power cable for the fuse box.

Now here is the weird thing, I tried to start the car and still nothing. Still the same message on screen. But decided to poke around the car while the key was on. Battery dropped to like 12.6v and all the previous locations where now reading like 6v if i grounded to the engine anywhere, but if i put the ground to my strut brace it read the same 12.6 as the battery.

Check all of the connections from battery forward, but especially the engine grounds.

And what is all the connections from battery forward? Be a bit more informative and not so vague with your responses please.

I'm not an expect of this platform, I know of some the obvious locations but just in case there are some hidden or unknown locations it would be more helpful if you told me what all connections to check instead of just "check connections".

As far as engine grounds goes, I only know of the 1 that is on the passenger side.

So I got the car to start and run, I can't say for sure what the solution was since I did multiple things at once, I removed a handful of fuses related to the ECM and the FPCM along with a few others. I also removed and reinstalled the ground cable from the passenger side of the engine to the ABS bracket. I've started the car up and drove it around a handful of times since I got it working again as well.

With that being said, I did originally have a check engine light from the 1st start up, checked it with HPTuners, had a bunch of codes, mostly related to stuff i disconnected, cleared them and went about my day with the car. I've not had a check engine light come on since, but I did decide to check the codes again since it's the end of the day and like i said i've drove it around a bit and i've started up a handful of times as well.

I still have the same two codes as originally, but now I also have extra codes too, and these won't go away even after clearing them.

EDIT: I'm not concern about the o2 codes since I don't have rear o2 anymore, and the car is tuned as well.

https://i.imgur.com/3YjRfJt.png

All of the wires that supply power or ground from the battery to where you find a problem. If you want me to supply you with a wiring diagram you are out of luck. If you want me to pick a particular connection and say that is your problem, you are out of luck. If you want me to teach you basic electric trouble shooting on a forum you are out of luck, etc. etc. etc.....