I have had intermittent problems with my top for 2 or 3 years. Usually when it failed it was early in the morning or after not being driven for a while but temperature didn't seem to be a factor. Typically after I had driven it for a while, the top would magically start working again. It also seemed to be seasonal. It would fail for a while and then work for months and months, though I really could pick up a calendar season as to when it would fail. Unfortunately or fortunately (depending on the perspective that it is easier to fix a problem that will consistently fail for you), it is no longer intermittent, it no longer works.

As best as I can tell, the failure is related to the package tray. My windows all go down, the trunk lid will pop up and then the roof starts retracting. The problem is that the roof stops being driven about halfway through the operation and it just starts drifting down. I finally realized that what is likely happening is that the package tray isn't popping up when it should and so the system shuts down. (Fortunately it never fails to go back, so it is a recoverable failure.)

So my guess is that either a sensor telling the roof control unit that it is time for the package tray to pop up is bad or the switch / motor control / motor driving the the package tray has failed. (If there are any cables involved, it is possible that a cable has popped off its pathway, though I'd think that I'd still hear some noise related to that and I don't.)

I'm planning on going to a dealer or the non-dealer "discount" Lexus shop and have them pull the code for the failure. Just haven't done that yet since they are about a 40 minute drive away. I have a sneaking suspicion that this is going to be really expensive to have it fixed.

Does anyone have diagrams of what the mechanisms are, what the controls are and where they are located (mainly for the package tray but the entire system would be helpful also)?

 

The top ecu is located in the trunk next to the fuse box under the carpet or lining in the trunk. When you take the fuse box lid off you can see the ecu, it's about in the middle of the trunk. Getting to the ecu is real easy. My ecu was bad and it took mi about 10-20 minutes to for the whole process.

 

Here is a picture of the top ecu

 

Thanks Tdvlexo. That helps.

 

Well, I finally broke down (no pun intended) and brought the car in to our "local" Lexus independent shop. (I say "local" since they are still a 30-40 minute drive away for me, just like the dealer.) I had waited so long just to make sure that it truly had failed this time and wasn't going to start working the second I drove into their parking lot.

So, of course, I get the call the next morning from the shop, guess what, it worked perfectly for them 5 or 6 times that afternoon. (Grr.) They continued to try and got it to fail the next morning, in a different manner than it had for me. They got it to go fully into the trunk and couldn't get it to come back out. (Fortunately, that never happened to me!) But at least it had the same failure mode of the package tray not working. And also guess what, NO ERROR CODES! (Grr again.)

So they hooked up more equipment to monitor the motor and still couldn't get it to fail, of course, until this morning. They finally caught it in the act of acting up (or down in this case). They were able to measure voltage on the motor (meaning that it should be on) and the motor wasn't running. So now they are going to have to order the motor. (Wow, Lexus is REALLY proud of their motors! I tried to find a used one but wasn't able to, not even on PartMyRide.) I did pass on to them the links various members here have suggested like Atlanta Lexus and MyLParts. (They were aware of the first but not the latter.) They said that there are only 19 of the motors available in the US. I guess that is a good indication of how reliable they have been, so far anyway.

To get to the motor, they said that they had to take the back seat out and a bunch of other stuff, so I was glad that I'm having them do it and get to the bottom of it. So sometime next week, I should be getting the car back, fully functional again after dealing with it for a few years, though the wallet will be extremely lighter.

Hopefully, no one else will ever deal with this problem but if they do, maybe this will help them debug their problems too.

 

That seems odd -- I wonder whether they have a tester that can record proprietary Lexus codes.

Well, hopefully the motor is the correct diagnosis and you'll be back on the road. As I always say, an SC without the convertible top is just a car.

Good luck!

 

Yes, they can read Lexus codes.

Thanks.

 

I've '03 SC 430 with the exact problem. Mine works for about 2-3 operations & gets stuck either while opening or closing. Based on the sound during operation, it appears to be due to the plastic cover that opens & closes between rear headrest & trunk lid or the trunk struts.

Let me know if replacing the motor solved your problem & how much you ended spending on parts & labor. Mine is currently with the dealer & they've been trying to simulate the problem with no luck.

 

Will do.

I finally figured out where the problem was after noticing that when the top stopped moving, the package tray was not up. This has been going on and off for at least 3 years with it working fine for many months in a row. (Typically, it would fail in the fall sometime and start working again and may not fail until the next fall. This time it started failing and never recovered for me, just for the mechanic, of course.)

It is definitely an illusive failure. You'd think that it has a dealer sensor in there also so it will know when to start working again.

 

I just got it back and it is working, so far anyway. Total cost was about $944.

Here's a picture of the motor. (It sure is a small little thing for $445!)

 

Thanks for the update and photo. I like to do a lot of my own repairs, but I think I would have taken this one in too. it looked like it would be a fair amount of work.

 

I meant to show the motor with a ruler to provide a size scale. Here it is along with the box that shows the part number.

 

Great illustration Harold, I too might defer this job to the dealer...

 

Hopefully, you guys won't have to. At least it was not a catastrophic failure I was dealing with.

 

Harold, did you get it done at Lexus Dealer for $944? Wonder why my dealer quote $2500 for parts & labor?