GA2004SC430

Rear deck won't close

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I have a 2004 SC430.  I put the top down this spring for the first time this year two weeks ago and when I went to close it the top came up and closed but the rear trunk deck stayed up and I haven't been able to close it since.  I have disconnected the battery hoping it would reset a switch but no luck.  The open/close switch now stays red constantly when the car is running.  I have used the manual trunk release to get into the trunk and check what I am able to there, still nothing,  What else can I check before I take it to the dealer and pay an arm and a leg?  Thanks for any assistance!

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Did you ever get this problem sorted out? The reason I ask is because I had a similar experience this morning except I was opening my top. The top folded in normally but then the rear deck and trunk sequence that was supposed to activate back to the down position just stopped with the trunk lid still open and the deck lid still in the up position. Tried resetting everything also. Ended up lifting the  hard top on the corners a couple  of inches  while it was packed in the trunk and then it closed completely and opened again with no further issues. So I was just curious if you had any luck.

Paul

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Hi Paul,

No I have not and because the top not closed alarm sounds continuously while driving, my car has been sitting in the garage for months.  What you describe is exactly what happened with ours.  My wife opened the top and she heard something and since then it hasn't worked properly.  I will try what you describe here to see if it works for us.

Thanks,

Dave

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Well for an update on mine, if I literally grab the top on the front drivers side corner while it is folded inside the trunk and lift it the inch or two, then let it drop back down, it allows a switch or whatever to reset and then starts working normally again. This has worked for me several times now. I used my scanner (an iCarsoft i905) and it identified a B2502 DTC "Open in Roof Drive Motor RH Circuit. I can clear the code and turn off the key then back on for another chance so to speak for the system to operate normally. Looking at the schematics in the Electical Schematics Manual, I see that there are ten motors, three ECU's and approximately thirteen switches. But the circuit itself is fairly simple. (I know that sounds counterintuitive  LOL) I have just been working on other things and haven't gotten around to identifying what the exact problem is since my work around has worked every time so far. My guess is I have a switch that is sticky and just the act of jogging the top allows it to set in its correct position. Yours could of course be something completely different but I just wanted to follow up and let you know where I am at with mine. Theres alot going on with the top. If the windows roll down the door ECU's are good, stuff like what works can help you narrow the problem down. Keep in touch. Lets see if we can work this out.

Paul20190713_104340.thumb.jpg.bf6d0f2e7cd519366e4547170a724247.jpg

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Paul,

Sounds good, I will try your fix and let you know if we have any luck.  I probably need to invest in a code reader since she has many lights on as well.  I need to put the battery charger on since the roof alarm has drained the battery!  

Thanks again,

Dave

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What we all need is a sequence chart. One that shows what is supposed to be happening and when. You press the top open switch and then the windows roll down, then the rear trunk lid opens, then the deck lid opens etc.

I have thought about it. It would be great if Lexus wasn't so stingy with their info sometimes. But hey, we aren't really the customers they are catering to are we e? 😉

Paul

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What we all need is a sequence chart. One that shows what is supposed to be happening and when. You press the top open switch and then the windows roll down, then the rear trunk lid opens, then the deck lid opens etc.

I have thought about it. It would be great if Lexus wasn't so stingy with their info sometimes. But hey, we aren't really the customers they are catering to are we e? 😉

Paul

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I agree 100%, knowing how something is supposed to work gets you more than half way to being able to fix the problem.  I bought ours for my wife six years ago and she loves it and refuses to give it up for anything else.  The size fits her perfectly as well as loving the hardtop/convertible feature.  If I can fix this top issue and get her back on the road she will be one happy lady!

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This is where I am at so far. More to follow as I get something useful.

Paul

 

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Wow, you have been busy.  As you said there is a lot of engineering that went into lowering and raising that top!

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Help with component location.

Package Tray is the black deck lid that pops open and closed at the front of the trunk area. Took me a few minutes to figure that one out.

If I had to make a guess right now, I would say that I need to look at the Limit Switches for the roof. That would be L11, L12, L13. They could very well just need to be inspected for being loose.

You said the top closed on yours but the trunk stayed open. That to me indicates a Limit Switch Roof Lock L10 or Limit Switch Roof Close L8, L9. Unless you can hear the roof locks engage. It might get ugly because the connectors for those switches are located in the body somewhere and if I am reading it right in the dash.

Are you afraid to take your platic covers apart in your trunk? Its not difficult. Just a pain. Now get to work and fix your wifes car! LOL.

Paul

 

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As an afterthought,  the pictures dont do you much good without know what the picture is. So, go to any of the aftermarket Lexus Parts websites and find the parts diagrams and P/N information.  That will give you a basic idea of the component name and its relative location. Good luck. Hope this helps. It should. And dont forget to come back and let us know what you find and what finally fixes the issue.

Paul

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Ok, inspired by your support I went to the garage and worked on her car this morning.  The top will go up and down but something is telling the trunk deck and the windows that the top isn't closed.  The red light on the top up/down switch stays red and the battery becomes drained.  I probably need to invest in the code reader to see what it is saying, at least that would help narrow things down.  Thanks again for your inspiration and encouragement!

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I agree with you, I think it is a limit switch that isn't recognizing the top being closed and therefore keeps the trunk deck up and the back windows down.  The locks on the top never engage either and that is one of the big reasons that we can't be driving it on the road unless the top is down and then the trunk deck isn't locked down either.  I can't physically do the work due to my disability.  When I was younger I would have but now it goes to the mechanic, even for oil changes.  

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Oh man. Sorry to hear about your disability. Getting old sucks. I turn 60 in two months but am still blessed with good health and a fairly sharp mind. 

Im still digging deeper and deeper into these drawings.  Man, talk about complicated. I have identified four ECU's now. And of course signal "x" has to be sent and received for signal "y" to execute. And prerequisite signal a, b, and c have to be there before anything can happen. But its interesting and I will nail it down.

Still working on a top up/down sequence in my head before I can commit to paper. And just identifying what the signal names are is a challenge also because they're not written down anywhere. 

So, you definately are going to need a scanner.  I do recommend the iCarSoft i905 because it has all of the test programs we need for our car. And it pays for itself the first time you use it since the dealer charges $150 bucks for a scan.

This is an important subject for SC430 owners. I'll try to take this through to some kind of logical conclusion but were actually talking about engineer level work if I include troubleshooting flow charts etc. and it will not be 100% acurate of course without being able to decompile the codes in the various ECU's.

But hey, anything at this point is better than what we have which is nothing.

Any components,  connectors etc you identify would be appreciated if you could drop a pic so we can see exactly what the manual is referencing. Especially if you remove covers.

Im not going anywhere. I'll do what I can to help anytime.

Paul

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OK. Something new to try. Lets assume that one of the limit switches for the top closed is bad or dirty or whatever. Take a pencil and insert it in the hole on the windshield frame like in the picture, both sides and work the hell out of that limit switch by moving that pencil in and out about 50 times. If the contact is just cruddy, that "may" help it start working again. Just a shot that doesn't cost anything. 

Paul

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That is a great idea, I will do this later today.  My wife keeps saying she is hoping it is just dirt on a track somewhere that is keep it from working correctly.  One of the issues with my disability is being unable to sleep through the night so I have been up for the past couple of hours.  I am turning 63 in November and have been battling health problems for the past several years so enjoy your good health while you are able.  I head to Jacksonville, FL next week to have some tests done and see a couple of doctors concerning some recent developments.

I think we have the identical cars at least cosmetically.  I took this picture shortly after I bought the car in 2012.  We have had problems with the clear coat going bad and had to repaint the drivers door a few years ago.  To be honest the entire car needs a repaint at this point.  We added the port so my wife could plug in her phone or ipod into the stereo which has worked out well.  A couple of years back we had to replace all of the catalytic converters, which the dealer wanted nearly $5,000 to do.  I took it to an exhaust shop and had it done for $1,200.  She loves this car but at times it is a love/hate thing for me since I am the one taking care of the problems when they happen.

Thanks again for the idea on the latching limit switches.  I will let you know what happens.

IMG_9755.JPG

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Well, the SC430 didn't really change much through its production life. New taillights in 05 I think. Suspension upgrades in 03 and 04 if I remember correctly.  You do have a different set of wheels than I do. I have the original ones that had the 10 bolt covers which the guys at the tire shop absolutely love. LOL. Removing 40 hex had bolts just to throw the tire on the balancing machine is what they live for. 😉

I just got mine back in April I think. Minor damage to the front and rear corners of the bumpers. Hazing of the clear coat on top and some door dings. Took it to a detail shop to see what they could do. Turns out there was a paint and body shop right across the driveway. Ended up with a new paint job and minor body work for the door dings etc. She looked great when she finally came out two months later. I live in San Diego and we have what we call May grey and June gloom. Conditions for laying down new paint were awful because of incorrect temps and humidity.  I told them they better not lay down that paint until conditions were right. So, it took two months. Told them no Orange Peel. So they sanded and buffed until she was pretty much a mirror. Wow she looked gorgeous.  But I had to be anal with my girl and she immediately left the paint shop to go for paint correction and ceramic coating.  Thats what finally made her pop into the most beautiful car I have ever owned. She is named Topless because she is so damn sexy.

She had 100641 miles when I picked her up. Now I am going through each system. Replaced all the coolant hoses a couple of weeks ago. Timing belt and serpentine  belt were replaced right before I bought her. I am waiting on all the vacuum and fuel vapor lines now. Shocks and struts are my next big ticket items because even though they are not really bad yet, they are leaking and they will need to be replaced. 100K miles, of course shocks and struts go bad. Then the drivers seat leather is of course looking crappy.

But I know how your wife feels.  I do love this car. 😎

Paul

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I found this diagram on another Lexus forum and thought you might be interested.  I wasn't able to clean the limit switched yet, it was a bad weekend health wise for me and was in bed most of the time.  Hopefully I will be able to get to cleaning them today.

Hope this diagram helps in your documentation of the roof sequencing and operation.

SC430 Roof motors.jpg

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Oh man! You are a STAR! This info is GOLD. Anyone who is having top problems should download this information immediately.  Good luck on your Doctors visit this week. I truely wish for the best outcome possible for you. 😁

Paul

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OK. Update time. Yea. 10 days ago, my top finally died. So sad. But, since I had the B2502 DTC Code to go by, I pulled the tire kit in the trunk and the center plastic to access the "Sliding Roof Control ECU. I removed plug S-20 and used my digital multimeter to check continuity across pins 2 and 6 to verify the health of the motor and cable to/from the ECU. Now a good reading would have been about 1 ohm. I had as expected something much higher. I think it was in the 40-50 thousand ohm range.  I found a replacement motor on ebay for $60.00 and installed it yesterday. Im back up and running normally. Took her out for a nice wash after. She looks so nice.

Yes. Theres alot of details missing.  How did I do this, how did I do that. Whats important to note here is that the hardest part was just figuring out how to get to the motor. Once I had verified the scanner diagnostic was good with the meter, and once I figured out how to get to the motor, it took me about an hour and a half to finish the whole repair. It really wasnt that bad.

I have definitely learned a heck of a lot about our top from this. I have had some really great people give me the information to figure this out. Having a scanner that could diagnose the top was the most important first step though.

As I wrote in a different post, "Why you should own a personal code reader" I wouldn't have known where to start without it. Have a great day everyone. 

Paul

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Hi Paul,

That is great news!  I am glad you were able to quickly and inexpensively repair your problem with the roof.  I will be purchasing a scanner so I can determine where my problem is and hope to have similar results as you.

Happy to hear you are back to enjoying her with the top down and returning back up when it is needed.

Dave

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Hey Dave. Glad your back and hope the trip went well. Yea, I might have another issue because I find it hard to believe that when the top was stuck while packed in the trunk that just lifting it and letting it drop back down made it work again was caused by the motor. Even though that was the only code ever called out. But hey, we can hope right? 

Paul

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Hey, I just had another thought trying to save you some money. Can you get the car to an Autozone or equivalent? They can run a free scan and if their scanner has the lexus DTC Top library, maybe we can find out for free. One thing I can tell after changing my motor, that top is heavy due to the gears. As far as the ding ding ding goes, turn up the radio or use the wrench in the trunk and try to lock the top through that plug just off center foward in the roof. Someone sent me the roof overhaul instructions while you were away plus I found how to manually open the roof etc.

Paul

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