Transmission issues - P0977 error 2005 4runner
 

P0977 OBD-II Trouble Code: Shift Solenoid B Control Circuit High
So this error and resultant driveability issues popped up on my 2005 runner, it appears stuck in gear 1.after it was left parked for 2weeks. It drove fine before this.

Scoured the forum and zero hits with p0977 error, the internet search says dirty fluid, bad harness etc. Checked the fluid, not so dirty..drained and replaced it.error persists.
Last fluid change was 5yrs ago/27k miles ago. And it drove fine since then

Strange that no one has encountered this error before

Could be corrosion in the electrical connector on the side of the transmission, this has been a issue on a few T4Rs, disconnecting it and reconnecting it may temperately solve the issue, but may need a better cleaning of the corrosion.

wow, nice, could you describe where this connector is, or better still a picture or thread?

Stumbled on this video on youtube, guess thats the connector you meant.

https://www.youtube.com/watch?v=v3C4tp_h1cI&feature=youtu.be

From what I remember it's on the diver's side as stated in the video, I don't know much else, I just remember reading about the connector and corrosion sometime being an issue.

The connector is tucked away in a hard to reach place.
Cudnt get to it after several attempts. Decided to do another drain and refill of the tranny while i was under the truck. Took the truck out for a spin, it drives ok now - knock on wood- , but the cel still popped out after clearing it. So guess the issue isnt resolved yet. Will try again to access the port,

I had a similar issue where I was stuck in some sort of limp mode. No CEL just couldnt accelerate at all. I had to floor it and barely got up to speed.
I was also told about the white connector on the transmission drivers side. You can unplug it and clean it with some de-ox-it, let it dry then spray some dielectric grease on it.
I never did any of this since this issue never came up again. It was a one time thing but its worth trying.

I remember a video froma few years ago similar to the one you posted, same problem with one of the pins, he also had a hard time accessing the connector to work on it, he ended up cutting a hole in the sheet metal on the inside of vehicle to get to it, after he "fixed" the pin/connector the same way as the guy did in the video you posted he patched the hole he cut.

I thinking the guy in the video you posted saw the video I mentioned above before he fixed his since they both "repaired" the connector/broken pin in the same fashion, or they both just came up with the same fix.

So you did absolutely nothing, no fluid change too?.
How long did the issue take to go away?.

Am having a fuel pump error as well, am wondering if its the fuel pump triggering the cel, and not the tranny error. Intend to replace the fuel pump, and observe further if the Cel goes away.

My thoughts on this problem (the connector being discussed) is that if I experience it and a pin is broken not going to try and repair as I think you may be able to replace the entire harness by dropping trans pan, disconnecting harness from all solenoids and pull it out and then thread a new harness in.
I've watched some rebuild videos on trans and it appears worth a try to me versus trying to replace a pin.

Yeah I did nothing. It only happened once for like 5 minutes until I got onto the freeway.

So the P0977 DTC is fairly straightforward:

P0977- ECM detects open in solenoid valve S2 circuit 2 times when
solenoid valve S2 is not operated (1−trip detection logic)

Possible Causes-
~ Open in shift solenoid valve S2 circuit
~ Shift solenoid valve S2
~ECM

I would snag a DMM and an inspection mirror and test the circuit from the ECM to the transmission junction/pass-through connector, and from the pass through connector to the solenoid in the valve body. While you have the connector disconnected inspect it for any fluid seepage/wicking and/or odd debris (I would also see if you can check the other side inside of the transmission, some of those pass-through connectors actually are just a plug that mounts in the transmission and is a go-between (though this parts pictures seems to show it as one piece). I have seen weird stuff end up somehow in between the connectors and short pins, I've also seen those plugs fail and start seeping/wicking transmission fluid causing issues (I think we even had one that wicked all the way back to the ECM and filled it up.)

Don't worry too much about the P0230 right now unless you're having starting issues, it's possibly it set when you had a poor cranking event.

Dropped the pan and drained and refilled. Then did another drain and refill 500 miles later. Car drives fairly ok now, even did a 300mile round trip recently, smooth shifting. Yet error code refused to go away, erased it several times, even unplugged the battery. Also removed the suspect solenoid from the tranny and tested it.tested ok with 12v and read 14.6ohm. So i wonder what the issue is, perhaps the cable tranny or ecm side.

Am still unable to unplug the cable harness, perhaps will try and buy the replacement cable harness to see if that will give me some insight in unplugging it. just not keen on spending money buying a part i may not need

could you give me a heads up on how to unclip the connector?