DTC P0766 Shift Solenoid D Performance / Stuck off (1 Viewer)

[landbruiser200]

Did a few searches for this issue on the forum and only came up with one thread that was slightly similar. Was driving on the highway a few days ago and the check engine light turned on, VSC, traction control and 4Lo lights, got the error codes read at my indie shop as follows :
DTC p0766 shift solenoid d performance / stuck off
P0776 pressure control solenoid b perf/off
P2714 pressure control solenoid D perf/off codes are present.
My mechanic doesn't work on trannys and suggested I get it priced at the dealership. Dealership says I need a new transmission for a ridiculous price. Any suggestions on how to proceed. Is this just a fluid replacement issue or something more involved. Thanks in advance.

 

[lx200inAR]

I don't have much help to offer, but i recognize the DTC. Someone else just recently started a thread on the same topic. Might join forces and see what you can figure out.

Hello and Shift/Pressure Solenoid Error Codes

Hello, In April, after years (over a decade!) of thinking about it, I pulled the trigger and purchased a new to me Series 200 Land Cruiser. She is a 2009 with 136,000 when I picked her up from a local dealership. She was really clean and according to the CarFax report, she spent most her days in...

forum.ih8mud.com

 

[landbruiser200]

appreciate it, saw that thread and posted in there as well.

 

[linuxgod]

What model year is your LC (and how many miles)? For the 2008-2015 models the P2714 code is "Transmission slipping" but for 2016+ models it's apparently "pressure control solenoid D". The description of the code you sent would actually match P2716. I would assume yours is a 2016+ but when I look at TIS the P0766 code seems to only exist for 2008-2015 models.

Assuming you're a 2008-2015, attached is the troubleshooting for the P0766 and P0776 codes.

If your vehicle was dropping into a lower gear on the highway (4th?) then it does sound like this issue. I spent all of 2 minutes looking at the attached, but the error code gets thrown because the transmission is slipping (rotational speed doesn't match what the gear should support). While you could need a whole new transmission, it's entirely possible that a solenoid is actually just bad and is a MUCH less expensive repair.

My laymen's method of attempting to fix this would be to do the following:

1. Go through the attached procedure and test the solenoids with a multimeter, do the active Techstream test (you'll need to go to a dealer, or you'll have to buy a $50 OBD dongle and install a copy of Techstream), etc. There's no reason to drop $5k on a new transmission for a $100 part and a couple hours of labor.
2. If the shop is sure the transmission is shot, do a full 12+ quart transmission fluid exchange. There's a procedure on the forum, but it basically just involves emptying fluid coming out of the cooler in the radiator and adding the same amount of fluid into the fill tube, until the old fluid starts coming out pink. My local dealer charges about $250 for this. You might waste $250, or you might find your fluid is old and burnt and this might bring everything back to life for you.
3. Failing the above, consider a transmission replacement

If your code is actually P2716 on the 2008-2015 or if you have a 2016+ then the troubleshooting procedure is similar to the above and should be done at the same time, and in that case most likely it's a bad solenoid and/or bad fluid and is a fairly inexpensive fix, I think.

Note that if your code is actually P2714 on the 2008-2015 that code is for transmission slipping and if that is the case and if the resistance for the solenoids in the attached test ok then you probably are out some $ as that indicates either a new torque converter or new transmission valve assembly is in order (or both)...

 

[landbruiser200]

Thanks for the valuable insight! It is a 2010 LX570. I had the codes read with my own scanner, my mechanic did the same with his own fancier scanner, then took it to the dealership for a full diagnostic and that's what they printed out, below screenshot. Those error codes are the end result all three times.

 

[linuxgod]

It's odd that the code descriptions for P2714 don't match what Toyota publishes in TIS.

What's your mileage?

The explanation feels like a worst case scenario for a mechanic who doesn't want to try to troubleshoot and fix the problem. The dealer knows if they replace the entire transmission your problem will go away. As an IT guy who fiddles with mechanical and electrical stuff, debugging problems takes some patience and an ability to walk through potential problem points methodically. I would say the vast majority of ASE-certified (and Toyota-certified) mechanics don't have that skill - they are trained in how to determine what system has the problem and then how to safely replace it.

Several years ago Acura told me I needed a new Nav unit. The unit would freeze up, or on start would post a failure message. $3500 estimate. I decided to run the self-diagnostics and it showed the DVD player for the maps was not working correctly. I removed the unit from under my seat, took it apart, and pulled out the DVD drive... matched the part # on the bottom and ordered a replacement for $65 off Alibaba. 3 weeks later it was fixed.

I would find a competent transmission repair shop. If a solenoid has failed it's going to be a couple hundred bucks to replace it. That's a far cry from needing an entirely new transmission, and the difference between swapping out an oil pump or a bad knock sensor vs replacing your entire engine.

Now in fairness you don't know the vehicle history and it's certainly possible someone towed a 10k # trailer in 6th gear over mountain passes and overheated the transmission, then continued to drive it afterwards without swapping the fluid, or flooded the vehicle in a river and then water ingress into the transmission diluted the fluid and caused this failure, but I personally would not drop $5k on a transmission simply based on P codes without someone walking through the manufacturer's troubleshooting procedure. Replacing the transmission based on a P code is like going under open heart surgery because your left arm is going numb - the codes are an indication there is a problem, but they don't necessarily tell you what the problem actually is and it's entirely possible something else triggered it (like you fell asleep on your arm) or that the sensor itself that sent the code is bad (like if you lost your arm so of course it's numb). In fact in your case if there was water infiltration (i.e. fog lights that won't go off) it's even possible there's a wet wiring harness connector shorting out and causing multiple codes to fire incorrectly, in which case a $5k transmission won't even solve the issue.

 

[landbruiser200]

@linuxgod I have 224k on the clock, never had any electrical issues, all lights working fine, recently acquired the rig from Texas. Lady drove it commuting from the suburbian outback to Houston proper daily, one owner car well maintained. I've put about 1k miles on it since acquiring it, have not towed anything or taken it off road. I reviewed the lex owners site and no indication of water damage, it was serviced at sterling mccall in Houston its whole life pretty much. Going to the specialist tranny shop tomorrow and will have them go through with a fine tooth comb to get to the bottom of it because 5k for a new tranny when it's most likely a sensor for a few hundred is just insanity.

 

[linuxgod]

@linuxgod I have 224k on the clock, never had any electrical issues, all lights working fine, recently acquired the rig from Texas. Lady drove it commuting from the suburbian outback to Houston proper daily, one owner car well maintained. I've put about 1k miles on it since acquiring it, have not towed anything or taken it off road. I reviewed the lex owners site and no indication of water damage, it was serviced at sterling mccall in Houston its whole life pretty much. Going to the specialist tranny shop tomorrow and will have them go through with a fine tooth comb to get to the bottom of it because 5k for a new tranny when it's most likely a sensor for a few hundred is just insanity.

It could be a sensor, or it could be the transmission needs to be rebuilt. Either way a good indy transmission shop should be able to fix or r&r for much less than the dealer cost for a new one installed.

224k is a bit higher mileage so it is possible it's starting to go, but if the solenoids test ok I'd seriously try a full fluid exchange before replacing the entire transmission. It's a $250 gamble but if the fluid is just old and no longer properly functioning you may get lucky - after all most people who aren't on this forum don't ever change their transmission fluid since it's a sealed system.

 

[landbruiser200]

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Is what my specialist indie shop recommended replacing. Ordered today should have it early next week.

 

[Sailcat]

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Is what my specialist indie shop recommended replacing. Ordered today should have it early next week.

What is what they recommended? What was the outcome? I'm having the same issue.