po770 shift solenoid fixed but not...

2002 3.4 liter, crew cab, 180,000 miles. Bought it near phoenix last week. The previous owner had "disabled" the check engine light and it wouldn't pass emissions. Any ways, fixed all the emissions stuff and CEL, driving back to the east coast, the CEL came on...PO770. Had the solenoid replaced in Asheville, ran it through three drive cycles, drove fine till last night. CEL again, same code. Same symptom, in cruise control, it will accelerate hard up to about 5 mph over the set speed then idle to about 5 mph below the set speed, then repeat the process. It has a new solenoid, the mechanic said the torque converter looked ok and it was achieving a good solid lock up fast. It doesn't drive too different out of cruise control, but there is a noticeable lack of smoothness when shifting, but ONLY when the CEL is on. Sometimes it's not on and it shifts fine, even in cruise control.

I'm thinking ECM/ECU or loose wire...

Any other ideas?

 

The ECM uses the signals from the Throttle Position Sensor and Air flow Meter to monitor the engagement condition of the lock up clutch. Then the ECM compares the engagement condition of the lock up clutch with the lock up schedule in the ECM memory to detect mechanical trouble of the shift solenoid valve SLU, valve body, torque converter clutch and automatic transmission assembly

I beleive you are going to be in for a rough ride on this one . I suppose the next step would be making sure the wiring is good going to the transmission and back to the ecu. I hope you have a scanner , a digital volt ohm meter and some wiring schematics to work with

There are many variables with this code meaning it could be a number of things as well as a combination of components considering the amount of miles you have

http://www.tacomaworld.com/forum/te...warner-340-series-transmissions-write-up.html

http://www.sonnax.com/parts/2764

http://www.transgo.com/products.php...d=253&countdisplay=1&start=0&addcountview=Yes



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Thank you for the information. Seems like I have my hands full. Looking at a diagnostic scan tool on Amazon now, any suggestions? I have a voltmeter, guess I'll start googling and printing up wiring schematics. If that's all properly connected, then you're suggesting one of the kits right?

 

Any scan tool should work for you but make sure the scanner is capable of displaying lock up commands for the torque converter .Your transmission doesnt use flex lock up technology thankfully . Your converter clutch is either commanded on or off . What would be nice in the scan tool is the ability to record parameters .This way , when code p0770 is set , you could sit at your desk and review the information rather than trying to decipher as you drive . I can imagine any scanner that offers real time recording is going to be pricey .
Those kits are a possibility to fix the issue . The problem with this code is the length of the diagnostic tree or breakdown of various things that need to be tested .
There is also a TSB out there for this code ...do a google search

 

Found this TSB thanks to you:

http://www.toyotapart.com/M.I.L._ON_DTC_P0770_T-EG025-02.pdf

Wonder if I can convince the dealership to do this about 100,000 miles late...Either way, much cheaper than a whole new tranny I'm sure. I'll let you know how it turns out. Thanks for pointing me in the right direction gear cruncher. Actually a million thanks