Well, just my luck, I went to go try to register the new to me 05 LS 430 at the DMV yesterday, and because I just bought the car I have to do a new smog check all over again even though the previous owner had the car registered and smogged just last month.I didn’t realize the recent smog would cancel itself out which sucks.

Anyways the check engine light suddenly turned on literally right after getting gas at a gas station. The car shifts fine and doesn’t seem to be slipping or hesitating. But after checking my code scanner it’s giving me a “Shift Solenoid C Performance or Stuck off” code.

I did see that the previous owner just had the transmission serviced. A new ECU was installed including new fluid, filter and pan gasket.

At the same time, who knows if the transmission shop actually did a good job since it’s located in the hood where I live and the shop looks pretty dirty and run down.

My concern after researching is that supposedly the transmission is failing? It states that it’s a solenoid problem, but does anyone know what the part # is? Is the job difficult to replace the shift solenoid? The car does have 157,000 miles on it which for these cars is nothing.

I’m fairly mechanically inclined and can do a lot of basic maintenance on my own, but I really want to make sure the job is done right the first time so I am more than likely going to have the transmission serviced again and replace the bad solenoid.

I appreciate anyone’s thoughts and inputs, and BTW the transmission shifts fine and is very smooth so I am totally confused and feel like I’ve been ripped off.

 

how much fluid did they use?
service of transmission is a drain and fill every 30,000 miles or so
this usually uses about 4 quarts of WS fluid
the smog thing is a California thing not done in the real world
If previous owner never serviced the unit and then tried to replace all the fluid there are some who have done this and had bad results
there are at least 3 different ways to replace fluid and all have their faults. Lexus designed for 100,000 miles of trouble free service to original owner and secondary owners are on their own. I would not trust my transmission to any shop that wanted to flush it.

 

On the bill it says they used 5 quarts of fluid. So it’s only 4 quarts per drain and refill? It’s possibly overfilled than. I don’t trust that this shop did a good job anyway, these transmission require a certain process to make sure the fluid change is done correctly, similarly to the LS 460 8 speed trans.

I plan on taking the car to a reputable transmission shop that I know of locally and see if they can get a firm diagnosis on exactly what’s going on.

 

I just had my ‘04 flushed at 220k miles. The fluid was super dark even after 2 drain and fills over the past 9 years. I, too, was anxious but I spoke to 3 separate independent Lexus shops and they all said the same thing that it needed to be totally exchanged at this point. I went ahead and did it and it shifts perfectly so far, maybe even smoother than before (also changed the engine and trans mounts which made a huge difference in smoothness). I’m not sure of the exact procedure that he used but he came highly recommended from a family friend and had worked previously at a Lexus dealer for a long time.

 

the transmission holds a lot more than 5 quarts so that is good also like you said it runs and shifts fine
units are very robust so doubtful any damage. I think total is 11.5 quarts in total but only about 7.5 in the transmission.
transmission will learn how you drive, mine is learning how to be in city traffic after small town, only car on the road where I was before.
my CL is black on black and I found it near Philadelphia 2 years ago. had it shipped to Texas and that added $1,300 to the price.
had a premium for 8 years and 90,000 miles and bought this one when I retired very hard to find CL,but that is what I wanted
sadly mine came with broken laser cruise and was very expensive repair, but maybe that is why it was so cheap

 

I thought about the car having to relearn the way I drive compared to previous owner might causing a issue.

Since I still need to smog the car, I cleared the codes and will need to drive it until all the systems come back being ready so I can get it to pass temporarily and get the car registered into my name.

I might do a flush at a shop so all the old fluid is out of the transmission if they feel like it’s safe to do. I will buy an OEM trans filter and gasket so I know I am using high quality parts as well.

It is strange hearing about transmission issues with these cars since they are so reliable, but like with any vehicle, if you neglect regular maintenance, even the best vehicles will break down and prematurely wear out.

 

Alright guys, I did the job with mixed results. I replaced the SLU, SLT and S3 solenoids.

First off, I knew something was amiss when the previous owner took the car to a transmission shop and they stated that they replaced ECM, the strainer, and added 5 quarts of fresh fluid.

I call BS because the fluid was dark red and smelled old but wasn’t bpitch black it was over filled, 4 quarts was drained but. You can definitely tell that the fluid wasn’t replaced if ever. The strainer looked original as well, plus I didn’t see any remnants of previous work being done, like removal of the drain pan bolts or exhaust bolts being removed. And supposedly the trans shop did all this back in September of this year.

There were a lot of metal shavings on the magnets, again, I could tell the pan was not cleaned at all therefore the shop lied about doing the job. Stay away from ghetto shops please.

After replacing the solenoids, strainer, gasket, and adding about 2.5 quarts of ATF, I didn’t have time to actually do the whole drain n refill procedure since I just didn’t have time and my body was sore as heck from laying under the car for hours, so I simply added the amount of ATF everyone recommended, I will do the proper drain n refill this weekend to make sure the level is perfect.

I was so excited because once I did the job, I took the car out for a drive and the transmission shifted perfectly fine. Every shift was smooth as liquid butter, but just last night I went for a drive, and the damn check engine comes on giving me the same P7061 “Shift Solenoid C Performance or Stuck Off” code.

The transmission went back into fail safe mode and the transmission would not upshift to gear.

I am completely at a loss, I spend about $500 for everything, mentally preparing to do the job and then actually doing it, hoping this was going to fix the problem.

Whats really strange is that the day when I decided to work on the car, when I started it up, the check engine light was actually turned off, weird. Then when I start the car and the CEL is on, it usually stays on and never just randomly turns off.

Could something be wrong with the ECM that was replaced? I mean how could the car run so good with me replacing the solenoids, adding some fresh fluid, run fine for 2 days, then all of sudden the CEL and same code pops back up? I would think if something was truly wrong with the transmission, wouldn’t the CEL come on instantly every time I start the car, and it not shift smooth at all?

Plus what was strange was the connector on the S3 solenoid was loose. It’s like someone messed with it before because the connector didn’t snap into the solenoid plug snug tight like the other connectors. Its on their, and doesn’t slip off or anything, it’s just something I noticed that could be of concern and should be tested for voltage to see if power is even being sent to that solenoid.

Also what I notice was before the CEL came on, the ABS light was flashing and red triangle 🔺 on the dash lit up. Including the VSC light on the dash.

Does anyone recommend me to try something else to see if I can fix this transmission issue before I decide to take it into a shop for additional diagnosis?

I did disconnect the battery to reset the computer, and the code still pops up. I am hoping I don’t need a rebuild since I just bought the car and can’t afford a small fortune to keep it, but the car does have 157k miles on it.

Thanks in advance guys.

 

So I’ve taken my 05 LS 430 to a trans shop and it’s been there for over a week. The technician has tested everything and he still doesn’t know what’s going on with it.

The car still has the code P0761 which is the Solenoid C stuck off code.

The tech tested the ECU and solenoid functions, which came out working properly. He thinks it could be a valve body problem. The passages could be clogged with small metal debris he says which could be causing the solenoid to be stuck.

Does anyone think it could be a valve body issue? What’s strange is that the car will shift fine in manual mode if after the transmission gets stuck in 3rd gear, I just need to come to a stop and then the car will shift ok. Just hope it’s nothing serious, I plan on taking the car to another shop for further diagnosis since this one couldn’t figure it out.

 

Send your ECU put to have it repaired. SIA or another vendor. This is a known issue. If the ECU hasnt been repaired before it needs to be addressed.

 

The technician said the ECU is fine and its sending signals to the solenoids which are turning on and off. The ECU was replaced on the car, but I have no idea if the ECU that was replaced was with a repaired one.

Also does it matter if the ECU part numbers are different? Because I noticed that the replacement one has a serial number of 89661-50781.

The old one that was in the trunk has a serial number of 89661-50780.

 

I just got off the phone with the previous transmission shop that worked on the car before the past owner sold the car to me.

The technician said that they replaced the ECU twice and had one sent out for repair which still didn’t fix the transmission code. He even told me he was stump and didn’t know what else to do.

So now I know it’s not a ECU issue, possibly I’m starting to think of the worst. Valve body replacement or transmission rebuild because nothing so far that I have done to the car has solved the problem. I might try doing a flush on the transmission to see if there is some small metal debris clogging the passages which might free up the solenoid from being stuck closed. If that doesn’t work, then either I sell the car for a loss or get the trans rebuilt or replaced with a lower mileage good healthy unit depending on how much it will cost me. If it’s going to be like $5,000-6,000 I’d rather sell it.

 

Having an issue with rough downshifts. Replaced the shift solenoid. Plan is to have the ecu refurbished first. If it doesn't fix the problem, the Toyota dealer suggests a new "rebuilt" transmission. They quoted me $4,600 complete. FYI, thought it might help. Open to suggestion, particularly on where to get the ECU refurbished.

 

I spoke with the technician that worked on my transmission today and he thinks that the valve body needs to be replaced as everything else checked out ok including all the solenoids and ECU. So now I plan on buying a nicely reconditioned valve body.

Thats crazy, $4,600? Did you consider going to a transmission shop vs the dealer? I would never go to the dealer for anything unless I absolutely had to or it was a last resort.

Try the ECU fix first, and possibly ask about the valve body having issues if the transmission is shifting fine and it’s not having any other problems instead of going for a full on rebuild.

 

Yes. The ECU numbers matter and are not interchangable. There are 4-6 different models that i recall and only the same part numver is interchangeabable. No programming required to swap same part number.

 

Ok, but both of the ECU’s didn’t fix the problem as the code is still there. So it’s not the ECU from
what I found out.