problems/ fixes maintenance and general info for 2010+ lexus is250c/350c convertible top only.
schematics, diagrams, pictures and procedures known to fix any issues concerning the retracting hardtop. there is very little information on this topic. hopefully together we can make it possible for owners to fix top problems themselves efficiently.

To manually close the hard top the user manual has a 25+ step emergency process you can follow

link to 1 type of common micro switches used in the top mechanism, (if you have links to any of the others switches please post i will add them)
https://www.digikey.com/en/products/...363860/9608182

common issue when hitting the top button with no response, the main switch comes unplugged. remove side panel and plug wires back into the switch. if this does not work replace the switch.

if hardtop operation gets suspended or the top gets stuck in the trunk, there is a manual key between the rear headrests.
option 2 disconnect battery for 15min, hold down trunk unlock button on keyfob while reattaching battery.

check your valet button is in the correct position.

thanks to to fellow is350c owner larrycheryl his thread link found below includes detailed information on the default state of all sensors for hardtop closed/opened position including screenshots, video of live sensor behavior/data while top is in operation, viewed on tech stream, 2 files also attached for tech stream users.
How to check what sensors are broken or not functioning properly using Toyota tech stream, https://www.clublexus.com/forums/is-...-sequence.html

thanks to DennisMik!, for taking the time to send me the service manual .pdf files for the convertible top, if you need them leave a comment or pm me i will post them or send them over by email.

if you have something to add to this guide post down below!

 

 

 

rear windscreen lock, sensor only on driverside

 

right side view of main package tray, 2 switches for postion, bottom switch for rear windshield lock on passenger side

main package tray motor/switch

 

pass side rear windshield motor/gears bracket

right side package tray/truck mount/motor lock sensors

left side package tray/ trunk mount

 

Husqvarna thank you for your post. We recently purchased a 2010 is250c and the convertible has not worked since we purchased it. The convertible is shut and there are no leaks but the OP SUSPENDED error blinks constantly when you turn it on. If we are not able to get the convertible fixed, is there a way to get that to stop flashing? Does anyone know what part is causing this light to flash, which latch, sensor, etc? It's obviously shut and drives just fine. Thanks for any input. New to this site and loving all the posts.

 

You would probably need Techstream to diagnose the exact error code. Could be something easy or something more difficult to fix.

 

You would probably need Techstream to diagnose the exact error code. Could be something easy or something more difficult to fix, depending on the error code.

 

hello jodan76 and welcome, you want to buy the techstream cable and software from amazon for around 45$, and read the error code with a laptop, once you tell us the error code we can better direct you to what sensor/sensors is causing a issue. question is there a gap in the front of the trunk near the back windows? if you try to lift up on the front side of the trunk is there wiggle room? at some point someone may have manually closed the top. after this procedure is finished you have to reset the system in techstream to relock the trunk mechanism completely. one other thing you might try is disconnecting the battery for 15min, this may fix your issue but may reset the code so reading the code should be done first. the hardtop on this this car is very complicated with 15motors an 37 sensors, it also communicates with the wheel speed sensors, the parking sensors, window sensors, valet button, and a few others, there is also a fuse box in the trunk you could check to see if any fuses have blown. if your windows are working fine and the trunk is unlocking and locking fine then it sounds like it is not a main package tray sensor, once you send us the code we can help you locate the correct sensor, you can also use the screenshots and videos larrychery posted to see exactly what sensor is acting up. there is a link to his thread in the first post. not only can we help you get the buzzer alarm off, we can help you get the top working again! good luck and keep us updated.

 

short version, order techstream from amazon for 45$ very useful tool, read the error code and post it so we can tell you what sensor is acting up, read the live data of all your top sensors, compare them to the default state of hardtop sensors from larrycheryls screenshots/video (link in first post of thread) that will tell you exactly what sensor is acting up. you may be able to manually reset it. or electronically reset it with techstream.

link to techstream that should work for you,

 

I am considering buying a very low mileage IS250C convertible hardtop-- but upon reading the difficulties that posters here have described with getting parts to fix that top when it malfunctions (and the very high cost-- as much as ~$12,000-- to have it repaired by the dealer), I am wondering if I would be making a very big mistake? I am in no way qualified, capable, or inclined to do the kind of extraordinary diagnosis, and DIY repairs that some of the extremely skilled members of this forum have described-- is that a prerequisite for living with one of these cars (which are all ~10 years old or more now, given that Lexus has not made them since 2015)?

I had wanted to own a Lexus forever-- and I really love convertibles; I especially liked the idea of owning a hard-top convertible that gives many of the benefits of a hard top, but still offers top-down driving. I had the impression (from talking to the few people I know who have owned one of these cars) that the convertible top mechanism on this car was extremely reliable-- and mostly trouble-free... but, upon reading the various threads here talking about some owners' issues, it began to sound like a nightmare issue-- one that I would be well warned to avoid...

I first checked out this forum, because the car inspection guru at the repair shop-- where I planned to take this car to be inspected, before buying it-- told me to avoid this car-- he said he had only worked on one of these IS250C cars before-- and the top was a major issue for that owner-- he said "Don't buy one of those cars."

I am trying to figure out if that repair shop's sample size is very small-- and perhaps skewed. I realize that the threads I searched for on this site were for problems with the convertible top mechanism on the iS250C-- so, I had naturally selected discussions that highlighted that problem-- and perhaps those posters constitute only a very small percentage of the owners of IS250C vehicles-- with most of them having NOT had issues with their cars' tops... but I would like to hear from others, who have owned this car: Is the top relatively trouble-free and reliable-- or is it a maintenance nightmare waiting to happen?

I am buying this car to be driven by my wife (who loves convertibles, too)-- it needs to be reliable.

Thank you in advance, for your thoughts and perspective on this issue-- they are highly appreciated.

 

Backing up a bit from just looking at a Make/model perspective of a car you like, generally speaking, if you are not mechanically inclined and don't have the $ to spend on a mechanic, you should stay away from older vehicles.

With that said, the hard top on the Lexus convertibles are very reliable. Not much goes wrong with them under normal circumstances - however, if something does malfunction or break, it can be an expensive fix. The most expensive part on the top is the "packaging tray" which has been discussed extensively in this forum. Lexus dealerships go by the book on repairs and unfortunately their go-to with pretty much any top malfunction is to replace those, to the tune of around $10,000. It's completely unnecessary in 99% of situations, but circling back to the mechanic bit - a simple switch or sensor to the tune of $15 might be enough to avoid that costly part. But, you would have to do it yourself.

Just my 2 cents. I wouldn't avoid this car anymore than I'd avoid any other used car 10+ years old. Good luck on your car search! Just remember - Lexus = Toyota. They're both extremely reliable brands.

 

Larrychery:

Thank you for your response-- you offer sound advice.
I can afford to pay a mechanic-- within reason-- to repair a car experiencing a problem-- but, paying a mechanic (whether a Lexus dealer or a third party mechanic) $10,000 (or even $12,000, as one poster here was quoted) to repair a car's convertible top-- when that is more than half the purchase price of the car-- does not seem like a good idea-- and if that is what I would be signing up for, by buying an IS 250C, then I may be making a mistake to purchase.

I read the extensive posts by various (highly skilled) DIY mechanics here, trying to find workarounds to paying Lexus exorbitant amounts of money to replace the entire convertible top actuator mechanism, solely because of a (very inexpensive) bad switch in the mechanism-- something that you have alluded to as well... What I really couldn't determine, from reading those posts, is whether this group of highly skilled DIY mechanics ever found the right switch (and the ability to insert it into the top actuator mechanism) in order to make the fix to the top only ~$15 (or even $50-$100)-- rather than $10,000 or $12,000...

The original posts on this topic are now more than ~10 years old-- the more recent ones started around 2016, and then there is another group of posts from ~2022-- what is the current "state of the art" in the ability to repair the IS 250/350C convertible top mechanism with inexpensive replacement switches and/or sensors? Has the group of informed experts on this forum determined that it is feasible to do that-- or are most people forced to go to the dealer for the really expensive full replacement of the actuator mechanism? (And is that even still feasible-- as perhaps, at some point, even Lexus will stop offering the replacement parts to dealers?)

 

I think it's twofold. The reason I think there aren't very many posts on here about the convertible top mechanism is because generally speaking, they don't break. It's pretty rare for malfunction. There are some threads on here about people who have had success with just replacing a few of the switches instead of the entire mechanism. I agree with you 100%, I spent $18,000 on my is350c and shelling out 10k in one repair would be ridiculous of a spend. Some people wrote up a few guides on this forum on how to determine which switch or sensor has failed. I also posted a full diagnostics video with all the convertible top parameters in working condition just to help other people.

The mechanic I take my Lexus to only works on Toyotas and Lexuses. I really just use him for general maintenance items that I don't want to deal with like changing oil and transmission fluid and such. What he told me when I asked him about buying an is350c is that he won't touch anything related to the top mechanism. He said it's just overly complex and he wouldn't want to bill someone guessing at what might be wrong with it. I'm also the only current repeat customer of his that has a is350c, so there's that too. It's just not that common of a car in general. So there's less information out there on how to repair things. Hope that helps you make a decision! I will say out of the 20 or so cars I've had in my life this is by far my favorite vehicle. I used to have a rag top convertible back in college and that thing was a maintenance nightmare. Mainly just because ragtops wear out. Replacing a ragtop can be upwards of 10k also. At least with this top, even if it doesn't work or the mechanism fails, you just end up having a 2 door hard top coupe. Doesn't affect the functionality of the vehicle otherwise.

One last thing that I strongly suggest you do before committing to purchasing a 250c is to go test drive a 350c. You won't want the 250 after the first time you put the pedal to the floor. The 250 in my opinion is underpowered. The 350 however shares the same engine as a Lotus Excige just to give you an idea. Also the most common issue that can be sort of a spendy fix on the 250 is carbon fouling. The 250 engine has a known defect that causes carbon to build up. There's a lot of people that have reported that problem. The 350 does not have that problem at all, and it's just an all-around better ride.

It took me 6 months to even find a 350 where I live. I could go buy a 250 right now no problem. 350s are hard to find, I had to take a 6-hour train ride to get mine. Lexus just didn't make very many of them.

Hope this helps!