2012 with Service Hybrid System warning

Hi all.
Hopefully someone can help enlighten me.
Our 2012 Prius had the Service Hybrid System message on Monday. Wife was sitting in the driveway when it happened. Car was recently started. She isn’t sure if the engine was running or not.
Car has 174,xxx on it, but has no issues.
Or didn’t until this anyway.

Several codes retrieved.
C2315 HV System
U0146 Lost communication with gateway A
U0073 Control Module Communication Bus A Off
U0123 Lost Communication with yaw rate sensor module
U0124 Lost communication with lateral acceleration sensor module
U0126 list communication with steering angle sensor
U0293 lost communication with hybrid/ev powertrain control module
U0100 lost communication with ECM/PCM A
U0129 lost communication with brake system control module
U0131 lost communication with power steering control module
U0151 lost communication with restraints control module
U0142 mainbody ECU communication circuit
U0155 lost communication with instrument panel cluster control module
U0140 lost communication with body control module
U1107 lost communication with power management module
B126A remote engine starter ECU communication stop

She had been driving off and on for a few hours by this time.
Car eventually started up and ran fine, except it displayed the errors.
I scanned it and cleared codes, and it seemed fine. I replaced the 12v battery, as it was original and showed reduced capacity, and I’d seen non hybrid vehicles show similar “lost communication” errors when batteries are weak.
Today it did it again. She’s put several hundred miles on it without issue until now.

Could this be related to the recall about the inverter software update? We didn’t know about it until I started looking into the issue and saw something about it. It’s actually scheduled for that tomorrow, so I’d assume they will check it over. I was hoping someone could at least tell me what to expect, though what’s going on with mine seems very different from other inverter or hybrid battery issues I’ve read about.

 

Dealer did the software (firmware?)update and says that should take care of it.
But if we have the issue again, bring it back.
No kidding? Lol.
Im hopeful this will take care of it, but they didn’t seem too knowledgeable about it, so I have my doubts too.
Time will tell.

Battery is new, and I don’t install a battery without checking it first. I’ve had more than one that wasn’t good right off the bat.

 

So, it isnt taken care of.
All codes back, and this time my wife had a loss of power.
Took it back today and they called and said we had an intake leak, per one of the codes.
The code in question is, according to my pre-dealership trip scan, and their scan, P0304.
Cylinder 4 Misfire detected.
They claim we asked them to diagnose it, which I denied. I said I asked them to find out why the recall reprogram didnt take care of the issues from the previous visit, all the codes, and "service hybrid system" warning we were getting.
The service manager then told me most of the same information.
I asked about the inverter, and she was clueless. I then mentioned that many times when the inverter is already damaged, the reprogram wont do anything, and did they check that? Again, clueless.
She now wants to check into some things with that particular recall and get back to us.

Im not saying with 100% certainty that the inverter is the issue, but since its the reason for the recall, why would you not check it to verify that it was most definitely NOT the issue?

Good grief. Why is it so hard to find a good dealership?

On top of that, I can no longer look up the recall number, as they reported it fixed so Toyota doesnt show it when I enter the VIN anymore. I suppose I can find it with a google search.

My wife asked me a good question after I got off the phone.
She wondered what would happen if she was alone, had no idea about cars, and took them at their word on this, paid the $1000 for the intake gasket replacement, then the problems came back. I said I guess youd keep taking it back until they finally figured it out.

 

So are we ignoring all the other codes about lost communication with other modules then?

It uses no coolant, so it seems unlikely its a head gasket issue, because if it were leaking enough coolant in the cylinder to cause a misfire, Id notice the level dropping with all the miles that are put on it in a month, and if it were pressurizing the coolant, basically the opposite of a leak into the cylinder, the pressure would be pushing coolant out, and again, Id notice the level change, if not the leak.
Is it that? I suppose however unlikely, its possible, but thats not whats causing the multiple codes about lost communication that started this whole thing.

 

First off, to all who are following this, offering advice, etc, thank you, and my apologies if I come across as short or snarky or whatever. That’s not my intention at all, just trying to sort this out as I have almost zero faith in the dealer to get it right and am very frustrated with that.
I wish I had another dealer close, but next one is over an hour away, though at this point I almost wish I’d have taken it there. Then again I could run into the exact same thing there.

Yes, it would be helpful to be more specific, and I will add them all. A few are different, but the number and type are similar. I suppose in my haste and frustration I was too quick and too vague which may have been (was) misleading.
Current codes as of yesterday.
* indicates new or different code from previous posted scan.

*P0304. Cylinder 4 misfire
U0146 lost communication with gateway A
U0129 lost communication with brake system control module
U0100 lost communication with ECM/pcm A
U0131 list communication with power steering control module
U0151 list communication with restraints control module
U0142 mainbody ecu communication circuit
U0155 lost communication with instrument panel cluster (ipc) control module
U0073 control module communication bus A off
U0140 lost communication with body control module
U0293 lost communication with hybrid/ev powertrain control module
U1107 lost communication with powertrain management module
B126A remote starter ecu communication stop


Codes from last scan not present now:
C2315 HV System
U0073 control module communication bus A off
U0123 lost communication with yaw rate sensor module
U0124 lost communication with lateral acceleration sensor module
U0126 lost communication with steering angle sensor module

 

So the weak battery was replaced, codes cleared, then all lights came back on, along with “service hybrid system” message a week and a half after replacement, and a week after Toyotas update, and it’s still related to the old battery that’s not there?
How is that possible?

Same here on the misfire.
I’m not concerned about the misfire. If it’s unrelated to the other codes coming and going, it’s an easy fix.
The random codes are the big concern here.

No on Techstream, used my BlueDriver twice, which are codes displayed here, and Snap On Zeus scanner once. Since it came up with the same, I figured it wasn’t necessary for getting codes a second time.

Apparently everyone is at a loss on this, which really stinks, because we really can’t be down a vehicle too long, and it’s been stone reliable to this point.
Seems like I always end up with the oddball issues.

 

Never cleaned EGR circuit.
What would this accomplish?

Software update just done by dealer after the first round of lights, service hybrid system warnings, etc. So about 2 weeks ago, which is where my concern for inverter damage comes from, but I’m also not sure that could cause these intermittent issues.

I have repaired a good bit of rodent wire damage, not on this vehicle or any of my own, but at the shop I work at, so that was one of my first thoughts, but nothing damaged that I can see anywhere.

Most times, with either cut wires, or chewed, the problem isn’t intermittent. These communication errors go 3-4 days to a week between incidents.