PCM replacement misdiagnosis?

My wife has a Honda SUV. It all of a sudden had a constant dead battery. Took it to a trusted dealer. They changed 2 batteries and I even bought one from an auto supply store which they installed. They did a number of electrical replacements and the whole while the service manager said he wanted to replace the PCM. We declined at first but after a couple of months he said he would replace it without cost to us. To our surprise after the PCM replacement and another fresh battery everything has been good. It might have been a great service manager and dealership but I wonder if there was some sort of hidden warranty. Couldn't hurt for you to pursue one for your vehicle and even try to contact the nearest Toyota corporate office. Try to deal with the highest level of manager possible. Good luck.

 

@badluckbetty

1)If the solenoid that was replaced was within the transmission, i.e. on the valve body, there is a reset/relearn procedure that is to be performed upon doing work on the valve body. Perhaps the servicing shop had no clue about this. I at this moment cannot help with where within Techstream that is located, but I have seen it there and I've seen it mentioned in manual excerpts on this forum.

2)The code write ups that I have read, personally I have no experience, say the code activates when the ECU detects a short or open in the wiring; wiring I think includes the solenoid too. You are now suspecting possible rodent wiring damage, so this may be right on track. The two main wiring connections to the transmission are all on the right-hand side of the transmission. I believe the wiring harness goes directly up the engine side of the firewall and through to behind the glove box, which is where the Engine ECU is located.

Good luck.

 

@canuck guy Damn sounds like yall lucked out with that dealer! That's a good idea. I'll try reaching out to corporate, thanks! Worth a shot at least.

 

@Toycoma2021

I will see if I can dig that up, thank you! They assured me they reset it, but definitely possible they didn't do it right.

Yeah, I'm still thinking wiring damage makes sense, but I took a good look underneath and under the hood today and didn't see any evidence of squirrels. Maybe I'm wrong but I just figured if they got in there I would probably see some chewed up wires in more obvious/accessible places too. Not ruling it out though, I think it might just be rubbing or pinched like someone suggested above. I'm curious about whether they thoroughly checked the connector too. Possible it could be related to a bent pin? I also checked some fuses while I was at it because why not (they were all good), and I disconnected the battery for a bit. After I reconnected it, I decided to see if the code was still active immediately after it reset and it wasn't. Drove a little to see if it came back and it didn't, although I'm sure it will at some point.

The local shop I was recommended is booked out til the end of the month. The downside to a mechanic with a good reputation! I wonder if it would be a good idea to take it to an auto electrical shop specifically instead of the dealer?

 

No answers for you at this point.

Here is a video I have enjoyed watching about our transmission. Ignore his accent and what he calls his vehicle. It is the same transmission AFAIK.
AC60E AC60F AWR6B45 Transmission Limp Mode Multiple Codes replace Loom/Harness & Auto Trans Service
The interesting damage is seen at ~4:00.

 

Nice! This is a much better visual representation than any of the other photos and videos I've found so far. Thank you!

 

Update! Took it to the dealership. They spent about three hours looking, couldn't find anything wrong with the wiring and assured me that the PCM is good. Notes on the invoice say "inspected the wiring harness from ECM to transmission main connector and found out of spec resistance for shift solenoid SLT" but I don't know how far out of spec it is.. they also said the new solenoid is working fine.

Now they want me to come back because "maybe it is the wiring harness, but we just couldn't find it." I asked what that would mean as far as repairs if they do find an issue, and they said "well, we would either have to replace the engine wiring harness or the transmission."

I asked them if there was anything wrong with my transmission. They said "no, but if we find an issue in the transmission wiring harness, we have to replace the whole transmission too." I asked them why they couldn't just repair or replace the wiring harness. The tech was like "uh.. well you just can't fix the wiring harness without replacing the transmission.." and I said "why not? I've seen a lot of people do it on Toyota forums by replacing connectors or splicing wires." He didn't know what to do with that lol

So, my next questions were a.) is it safe to drive and b.) am I going to cause further damage by driving it? He said yes, it is safe to drive and no, it will not cause further damage. So I guess I'm just going to keep driving it unless something else pops up. CEL still hasn't come back either!