Have a 2002 SC430 and hardtop is not opening. Had worked perfectly, but don't open it often. I noticed that the Power Windows recently stopped working on Auto Up/Dn on driver's door and passenger door, but holding the Power Window buttons work fine. Would this affect it since they are controlled by the hardtop's trunk ECU? Roof Open Switch light does not work, i.e., nothing happens. I did replace the radio antenna recently after breaking it accidentally. Used the converter kit from Antenna source. No problems with installation. Antenna motor still runs as I recall.

I had a Lexus-Only private shop mechanic with 25 years experience check it. He tried resetting the Windows several times, but this did not correct the Auto Up/Dn problem. Fuses in Trunk and Passenger Side Box are OK. He visually inspected the switches in rear of car, and they appear to be OK. Cargo Cover pulled back into slots. When Open switch on dashboard is pressed, Nothing happens. He checked OBD codes and no faulty codes were indicated. He said the code reader showed no response or connection to the hardtop's ECU. He could not find anything in his Lexus manuals indicating that the antenna might cause this Roof problem. I would appreciate suggestions on this anomaly.

I have read a number of the Forum's SC430 Hardtop recommendations for problems. One in 2018 Posted by Peeek had somewhat similar problems, and VVTiBob had good recommendations. That Hardtop's ECU had to be replaced.

 

Is your valet switch turned on? (It is in the glove box.) With that turned on, the roof open switch is disabled.

 

Just checked, and it is pressed in which should be correct.

 

My mechanic likely checked the trunk lid switch since I saw him open the glove box and look inside. He didn't tell me what he was checking. I remembered that a forum recommendation was to do a full system reset by disconnecting the battery for 30 minutes. I just did that with the battery cable off for an hour Tried the roof again and no luck. Still no lights on roof open switch. There was also a suggestion to operate a full roof open and close manually, but I don't know how to do that.

 

No techstream diagnostic? This will give you the answer immediately.
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My Lexus mechanic used a computer connected to the car's port and, separately, what looked like a handheld, but very long, meter somewhat similar to a huge volt/ohm meter. He read the diagnostics and said nothing was showing an error code. I can check with him on Tuesday if there is something specific to consider with the meter. He only added that the readings said that there was no response from the hardtop's ECU box.

 

Yeah, if techstream can't communicate with the roof ECU that's is your most likely culprit. Sounds like he knows what he is doing if he has the software.

 

If the windows dont roll down first, nothing is going to happen. You need to disconnect the battery first. Clear the system out. Then hit the button. If the rear and front driver and passenger side windows dont roll down, thats where you begin troubleshooting.

Paul

 

Paul, that's what I tried this afternoon after having the battery cable off for about an hour. Nothing happened when I started the car and pushed the Roof Down button.

 

OK. This I can tell you for certain, everything you need to troubleshoot this problem is on this site. But, its highly unlikely that it is the top. And thats all I can tell you. Without a scanner or Techstream, you have almost no chance of figuring it out. But you can start here I guess. Good luck.

Paul

 

As Paul said, if the windows don’t roll down, your top will not open. Since you are able to roll the windows up and down manually, this part of circuitry is fine. Your most likely problem is the roof ECU.

 

Well, the nice thing is you can get a used "Sliding Roof ECU" on ebay for about $100 shipped.

Paul

 

Wow, all of your suggestions are great, and I appreciate them! I do trust my mechanic, and he recommended for me to post the problems with the roof on the Forum to see if he had overlooked anything since he doesn't work on the SC430 often, and the roof not opening hasn't happened before to one that a customer brought in. He said if something else didn't show up from your recommendations, then it probably is the Roof ECU. He wants to check the ground on the factory unit after we have access to it. If it's, good then we'll replace it with one from Ebay or he has a rebuilt source.

He's very busy, so I thought that I would remove the rear panels. I saw that there's a post somewhere on the Forum for doing this. I looked as best as I could, and I haven't found it. There is a good three-part video on-line about removing the panels on the right side to replace the antenna unit. I'm happy to search further on the Forum for this post. Since I'm new here, do you have any hints about how to do this more efficiently? Mrblister posted on the Forum that it should take a novice about 45 minutes to pull them. That means about 90 minutes for me.

 

I purchased a returnable and used Roof ECU on ebay for $40. VIPNISS was also helpful in sending me the link to his photos and information on removing the trunk panels. I removed them easily with this information, and I took the used ECU to my mechanic who installed it. The roof worked perfectly, and the power windows switch for auto up/down now works as well! The trunk panels are now back in place, and everything is working properly!

So thanks again to each of you who responded with suggestions which I tried first and on finding the replacement unit!.I sincerely appreciate your help! Oh, my wife is also pleased that the top goes down again, and we can enjoy the SC430 as a convertible.