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What is the likely outcome of *not* resolving the P0763 "Shift Solenoid C Electrical Malfunction" issue? I have a '98 GS300 with 96,600 miles that has been throwing the P0763 code for a while. It seems to be shifting ok. I don't drive it much anymore and I'm trying not to put much more money into it.
I've heard that incorrect ATF fluid levels or dirty/old ATF could cause P0763(among many other causes). Today, I checked the transmission fluid level while idling and noticed it was quite a bit higher than the "hot" level range(see pic). I drained some fluid to bring it down to the correct level, cleared the codes, retested it and it's still giving the P0763 code. I realize it may take some driving to "clear out" the issue and possible stop throwing the code (I'm skeptical though).
So, What is the risk/danger of *not* resolving the P0763 "Shift Solenoid C Electrical Malfunction" issue? If I don't address it is it likely it'll cause more damage? If so what type of damage.
(Thanks to all for a great thread) - John ATF Level before draining some fluid
Last edited by John4857; 02-13-20 at 11:08 AM.
Reason: added picture
Hey,
wondering if you ever resolved the p0763 issue on your car. I have the same thing going on. Cel comes and goes but there is no discernable issue with the tranny. It shifts fine.
Hey,
wondering if you ever resolved the p0763 issue on your car. I have the same thing going on. Cel comes and goes but there is no discernable issue with the tranny. It shifts fine.
No.
I never bothered.
I just put up with a 3-speed transmission. 🤣
Never got any better, never got worse.
AFAIK, car is still running (sold it last year, and it's still taxed/insured up to last month when I checked).
Someone recommended "seafoam" transmission cleaner as a possible solution to a sticky solenoid - but I needed an estate/station wagon so bought a sportcross instead.
I know this is a very old thread, but I just got my gs 2000. Replacing a shift solenoid “C” will run about a grand. The solenoid itself is $399. Fun that Lexus quoted 549 or whatever 15 yrs ago. Anybody hear different?
I just paid an Indy to fix it. Very expensive, but I don’t have the patience to deal with everything people on this thread have done and not have it fixed. I’ve never been lucky enough to have it be something as simple as a fluid change
Hi, I had P0715 and P0763 alarm codes on my Mk2 GS300, Drained gearbox, Dropped gearbox pan, cleaned all solenoids, changed filter and gaskets and put new oil in. Still got alarms, the mechanic I use to service LPG checked, and he says alarm now is related to harness, he checked outside sensors on gearbox and he thinks seals are gone because theres oil in the connectors? Anyway, I checked the amount of oil in gearbox when hot, way too much in there. After a lot of syphoning ended up taking almost 2 liters of excess oil out of box, so with that excess there was pressure build up and heating up as well. After I done this took the car for a drive, a hell of a lot better, faster gear changing better acceleration, VSC off and VSC alarms and engine management still on but no P0715 or P0763.Annoying me now. I eventually got in touch with Lexus Cardiff, because the Toyota garage in Swansea can't work on Lexus anymore, and Cardiff have only one guy who works on older Lexus and he was on holiday,I will keep you updated as to if and when it gets resolved.
Solenoid 35230-30010 was bad in mine as well. Ohms tested good initially but when pushing and pulling on the terminal it would lose connection intermittently. Thought I would add another data point to this thread. Thank you so much to everyone contributing and making this an easy fix for me. My symptoms were P0763 code and clunky gear shifting in basically all gears.
Quick update, car running fine, sometimes engine management light comes on, next doesn't, still got VSC OFF and VSC alarms but only when car starts moving.
Now found out the wiring harness inside the gearbox needs to be changed. (Where the hell do I get one of them?),anybody have any ideas, apart from getting another gearbox?
Codes P0715 and P0763 for last couple of months. Took it to the LPG garage I use,(Because nobody else wanted to touch the job, not even the Lexus dealer). they dropped the tranny pan, cleaned all solenoids, changed filter,(which was black with burnt oil), and ATF. The oil looked a bit burnt but all clear now. VSC and VSC off and engine management lights still on. cleared all, but come back on after driving away. When I got home I checked ATF, too much in there, after draining with large syringe for 1.5hrs ended up taking 2 litres of excess oil out.(Forgot to tell them to check when hot and the different levels on dip stick), Took car out for a blast, I could feel the difference straight away, so the excess oil was getting too hot and also there must have been a lot of pressure. didn't realise it would go faster as well as change smoother. Still got VSC and VSC off alarms and garage has checked it out and he says its the wiring harness. Can you even buy one of them? So I've got to find one of them, and do the same again and hope it works, fingers crossed for the 12th time.
I have bought a really good second hand gearbox, would it be easier to swap the harness or the whole box? See above post. Decided to change harness,
Altogether, Drained oil and cleaned solenoids S1 and S3,new oil and filters and gasket. No difference. Found after doing this mechanic had put 2 litres too much oil back in gearbox. After draining excess oil car felt different and gear change faster but still alarm codes?. Changed both solenoids for ones out of low mileage gearbox new gasket and filter again. No difference. Put new wiring harness in, changed all solenoids, (just in case), and once again filter and gasket. No alarms till car starts moving, engine light stays off but VSC and VSC off lights up. Did the reset on zero point of yaw, and decceeration sensor,(If anybody wants that info it's on AintBigAintClever youtube site), everything now working and no alarm codes.
Last edited by Royblackmore; 11-06-23 at 04:28 AM.
Reason: Job finished,wanted to update info
Take small amts out via dipstick $27 electric fluid pump at Temu.com
Originally Posted by wise2k
i have a 98 gs300, 177k miles and i have that code; bought the car with the code at 174k miles, and when i checked the fluid it seems way too much, about double the range - above the "hot" level. how do i bleed it out a little..? maybe that could fix it. Otherwise, it's a 3 speed car right now I get in the car, put it in d5, give it gas and it almost instantly shifts to what feels like from 1st to 3rd (could be 4th), and then from there it has one more shift to the final gear which does feel like 5th, but seems there is no overdrive and you can only imagine how much gas i put in it, and i can never try and make a quick left in busy traffic because car has no power due to higher gears engaged.
take small amts out via dipstick with electric fluid pump. Got mine from temu.com $27
i just got done changing the solenoid. had code P0763
it had come and gone once or twice momentarily in the past. it came back on after draining the pan and filling with fresh toyota tiv fluid. it was intermittent but getting worse until i decided to drain and refill again.
it immediately went away, and the car shifted beautifully for 3 days. on the 4th, the code can back with only 3 gears active 1,3,5. it also shifted way too early. it would go away and come back, sometimes after a couple minutes, sometimes after a few miles, sometimes not for a week, and then only to come back at cold start.
i bought an oem solenoid from an amazon vendor for $180. drained pan and loosened all pan bolts. it was a minor difficulty removing the pan because of an exhaust bracket in the way. luckily, while the bracket bolts were rusty, they came out with a breaker bar and minimal effort. i only removed one side and the two middle ones so i could swing it down and out of the way.
the forward momentum youtube channel probably has the best video showing the removal up to this point.
aside from having the factory repair manual, watching several videos, and reading many posts prior indicating which solenoid the 'C' was, there is only one whose appearance matches the new oem replacement.
i also purchased a fel pro pan gasket, and the autozone duralast kit to get the filter. i thouroughly cleaned the pan and magnets, and used a wire wheel brush to remove the old FIPG material from the pan. a chisel and green brillo pad made easy work of the transmission side of things, so both sides were clean and free of old gasket material.
i had intended on experimenting with the old solenoid and cleaning the others, but the plastic of the electrical connectors was extremely brittle. i removed one and it looked fine so no code no problem don't screw with it.
the job required only an 8mm, 10mm, and 14mm. i did use a breaker bar and a 1/4" hex impact driver to keep things easy.
the only surprise was at the end refilling the atf. i had 3 and 2/3 bottles of toyota tiv on hand, and added all of it and my dip stick still reads low. i did allow for atf to keep dripping to reduce the mess (no spills, covered the whole area with carpet, cardboard, and sacrificial towels). i didn't anticipate having to replace so much fluid.
anyways, the code is gone and the trans sounds good. it's got that nice whine n slide to it.
the old solenoid did not read any resistance when checks vs the 12.7ohms of the new one. this is why i didn't attempt to salvage the old one at all. inspecting it just now, i can see that the solenoid failed open, and applying pressure to the input pin causes it to make contact internally and read the correct resistance spec. i've seen a video showing this same failure and was repaired by prying the solenoid apart and resoldering the broken connection.
i took my time and moved slowly and carefully, i think it was 3.5 hours to do the job itself and then i spent another 2 hours between slowly adding fluid, a couple test drives, and cleaning up.
edit: i have a 1999 gs400. the part number for shift solenoid 'C' is 35230-30010
Last edited by 400gs99; 04-28-24 at 10:15 AM.
Reason: additional info
02-13-20, 11:03 AM
I get in the car, put it in d5, give it gas and it almost instantly shifts to what feels like from 1st to 3rd (could be 4th), and then from there it has one more shift to the final gear which does feel like 5th, but seems there is no overdrive and you can only imagine how much gas i put in it, and i can never try and make a quick left in busy traffic because car has no power due to higher gears engaged.
