I'm just posting this in case it will help someone else. A few months ago I got an engine light code p0770 shift solenoid e. My car start developing symptoms like before coming to a complete stop it would sputter and feel like the engine is about to stall then the rpm needle would instantly kick back up and the car would slightly jerk then drive normal until I start coming to a stop a again. Another cl member had the exact same problem and he ended up replacing his transmission.

So I researched and decided I would replace the offending solenoid which is a lock solenoid aka SLT EPC. This solenoid is the MOST expensive one out of the four solenoids in the trans. It cost $287 from Sewell and over $300 from everywhere else online. So what I did was was call around to some wrecking yards, and I convince one to sell me all four solenoids for $140. They came off a 97 LS (same yr as mine), the car only had 140k on it.

I sprayed the solenoid down with CRC MAF cleaner, let it dry for a day and installed it the next day. End result problem solved!

The code have NOT came back on, and my car is driving and shifting just fine. NO more sputtering when coming to complete stops and no more weird shifting.

Other members have recommended replacing ECU caps first, but I say replace the solenoid first and pray it works.

As for the other 3 solenoids? Two of them are going on my 91 ls400, it needs two shift solenoids.

 

I just worked on the same problem. I tested the Shift Solenoid SLU closet one to the front of the car. P0770 code. Placed 12V on the pin and it does not move... It also rattles when I shake it.... Anyone know where to get a good used one... I do not want to pay 250 Plus for a new one? Thanks

 

Even if you can't find one its still cheaper than what a trans shop would charge.

 

^^^^yup what he said and $250-300 is better than paying $1500-2000 to replace the whole transmission

If you don't want to pay $300 for that solenoid, then your only option is the wrecking yard and hope that they will even sell the solenoid alone, they want you to buy the whole transmission most of the time. Also if the trans is not pulled you or one of them have to get under the car and get the solenoid which is NOT fun, I did it because I didn't want no one to damage the part during removal and it made for good practice since it was my first time.

BTW I hope you have the right solenoid in mind, the one I replace is the big dark grey one with numbers inscribed on it. You have to remove the oil strainer to get access to it.

 

Yes, I just doubled checked it.... it is the larger dark grey one closest to the front of the car... I found a good document on line on how to test it. The ohm reading on mine didn't make sense, but when I shake mine it rattles like something is broke inside the solenoid section of the part.... I have attached a photo of the part and the test doc.

 

Yep that's it. Don't worry about testing it, if your car have p0770 code then the solenoid is no good, I would just replace it. Find a used one if you can, if not then buy a brand new one, yea its pricey at 300 but at least your transmission will be fixed.

 

Update, unfortunately the p0770 code came back 2 months later and my car slowly started to develop the same symptoms in my original post, sputtering when coming to a complete stop and slightly jerking when accelerating from a stop. So I bit the bullet and ordered a brand new solenoid from Sewell Lexus for $297, installed it myself and car is back to driven normal, no more sputtering and jerking.

Also I made an error in my original post, I said this is the SLT EPC solenoid, that is INCORRECT, this solenoid is known as the "SL lock up" solenoid on 90-97 Ls400s part # is 3528050010.

So if you have p0770 or any other related solenoid codes I recommend buying them new, although there are cl members who have replace solenoids with used ones with no problems.

 

So then whats happening is the lock up solenoid being broke must allow some pressure to the lock up clutch, and causes the torque converter to drag down the engine similar to a manual transmission and not pushing in the clutch at a stop. Also this is not good for that clutch so if that happens fix it now don't wait.

And from what I read here its probably best to fork over for a new one as a used one may be on the brink of failure. In the end doing the wrecking yard replacement didn't save much. The time spent and the extra fluid, gasket etc.

 

Things are often not very simple as you think. I worry that your new solenoid will be failing again without finding and countermeasuring the root cause of your failure. Hope you don't repeat spending $297 any more.

Your description "my car slowly started to develop the same symptoms in my original post" indicates that the problem did not start all of a sudden. This alone tells the hint. If it were a single solenoid problem, there should be an obvious turning point to fail.

There must be some reason which damages the solenoid little by little. I would check it including the controlling circuit.

 

Well only time will tell but so far the car is driving great. But let me clarify a few things. Idk if it had anything to do with it, but everything was fine until one day I decided to put some castrol atf in my transmission then I got p0770 afterwards.

When I replaced the solenoid the first time I got the part from the wrecking yard, and it did work for 2 months then the p0770 code came back FIRST then the car started to develop symptoms. But I drove the car almost a month with the code.

Now with the new solenoid i do notice that the car do drive better this time around then it did with that used solenoid from the wrecking yard. Mabey that used solenoid was on its way out anyway mabey. I can do an update in 90 days, if the code don't come back in 90 days then everything should be OK.

Forgot to mentioned, that the solenoid from the wrecking yard I sprayed it with CRC Mass airflow cleaner, let it dry then installed it.

Update 8/5/15 11:46 pm. Well its been about two months since I replaced that solenoid and the p0770 code still have NOT come back. I think it's safe to say that my p0770 is fixed.

 

Thank you for posting this. I have same problem with my 2001 Lexus ES300. It simply jerked twice and I felt it is not smooth shifting as you accelerate. I took it to AutoZone and they checked and told me the code was P0770. I removed the battery terminal and reset the code just to see if it comes back. It did not and car ran just fine for next 60 miles. Next day, it just stop moving on the free way. The code never came back on. It is in the garage and the guy says it needs new transmission. Any suggestions??

 

P0770 is the converter lock-up solenoid. When your car quit, did it also kill the engine? The converter clutch may not be releasing causing it to kill the engine. If the converter clutch is not applying at all it will effect fuel mileage or heat up the ATF enough to where it can cause internal damage. Is the ATF still bright red or does it appear/smell burnt?