[MattinLA]

Hi, my transmission has been rebuilt, getting these P0770 errors usually when going up a hill, my rebuilder says all sensors are good, car rides excellent he maintains it is the CPU at fault, does this seem reasonable, what else can the problem be.

[driffter33]

Not sure what that code is but it could be a bad wire connection, or wire.

[Deep_palancar]

Following my transmission rebuilt and torque converter replacement I chased a P0770 for several months. After verifying that all the signals were correct and that the solenoid itself was good, I finally replaced the rebuilt torque converter with a used one from a like truck and the problems were cured.

During my research I learned that the ECU is extremely critical about the timing of the lockup signal and lockup detection as well as unlock signal to action time.

[mpowers]

I am having the same code no problems shifting or uplocking.
How did you know it was the TC?

[MattinLA]

You replied to the wrong user.

[MattinLA]

The TC is not what usually calls a P0770 error! If your TC is bad, it should be making a scary noise like marbles banging around in the engine because the fins are breaking apart inside. Usually a bad shift solenoid is to blame so don't be paying some huge repair bill if that does NOT cure the problem.
You better be watchful of this! Did they attempt replacement of the solenoid? TC replacement may not be THE CORRECT REPAIR HERE!

"The ECM uses signals from throttle position sensor, airflow meter and crankshaft position sensor to monitor engagement of Torque Converter Clutch (TCC).

The ECM compares engagement condition of TCC with lock-up schedule in memory to detect MECHANICAL trouble of lock-up solenoid, valve body and torque converter. A P0770 trouble code is set when TCC lock-up does not occur during appropriate speed, or lock-up does not release at appropriate speed.

Possible causes are:
* Solenoid is stuck open or closed.
* Valve body clogged or valve stuck.
* TCC malfunction."

[HOGG1335]

Does anyone have a part number for this solenoid? Just got this code on my 1999 4runner 2.6. Please help. new to this site.

[Racer_C]

I have a 2001 supercharged 4/Runner. I use Valvoline synthetic fluids in everything. Tranny replaced at 258k. Have 130k on remanufactured tranny (3 year warranty expired), when this code P0770 code popped up on my Bluetooth code reader as pending. Had no other warning signs there was a problem, as it drove fine. After two consecutive highway drives the code would light up the check engine light.

Replaced all three solenoids with non-Denso solenoids. [Don’t buy from Five Star Transmission Parts. Only 1 solenoid was correct, the other two were not as well as the oil filter. They led me on as if they were sending me the correct parts. Waited a week. Never arrived Bought correct parts on Amazon.] I normally always buy Toyota/Denso replacement parts, but I didn’t want to pay the crazy prices for these solenoids. Codes haven’t come come back since replaced. Still a tad skeptical replacing the solenoids were the solution (and in part, why I didn’t buy Denso solenoids), but very happy if remain error code free. Also, trans temps seem to be running cooler, but it’s not summer so a little hard to tell, since didn’t really pay attention to them before, and haven’t had the Bluetooth reader until recently, when when engine was remanufactured summer of 2020.

Just in case, I have been looking for a new tranny. I found one with a five year warranty and free shipping. reman-transmission.com. Note: this is somewhat of a note to myself, for when I do need another one. I like the warranty and free shipping. If anyone has any opinions on this company, please speak up. Thank you!

Btw, don’t mention you have a supercharged motor. I called one place with questions, and the moment I mentioned supercharger, the person became kind of a jerk, and wanted to be very clear no warranty, and their transmission was not for me. He could’ve been nicer about it. In the end, glad he was, because that’s when I found this place with better warranty.

Good luck to all with this e shift solenoid P0770 problem!

[pj_o44]

I am fighting a P0770 nightmare. Shift solinoid keeps failing causing the TC to not lock up. Replaced 3 times. Last a couple days then fails. Shop doesn't know how to fix it. I will have to take it somewhere else.

[spartacus]

Originally Posted by pj_o44

I am fighting a P0770 nightmare. Shift solinoid keeps failing causing the TC to not lock up. Replaced 3 times. Last a couple days then fails. Shop doesn't know how to fix it. I will have to take it somewhere else.

Some times a bad tps sensor can make the TC not lockup. Tps sensors are relatively inexpensive