I would check the sunroof drain hose integrity. If you look at the parts diagram, the hoses are routed towards the rear of the headliner.

 

but that means taking down the headliner 😣

 

I would be taking a really good look at your shark fin seal.

 

I'm having this issue on my 2013 Lexus GX 460. Did you find out why it's leaking? Please and thank you!

 

A side thought… A power washer around the shark fin would emulate a car wash as well.

This is typically the leak point for the rear areas

 

Monday I drove through a high pressure touch less car wash. The back of my head got wet and I noticed some water in the passenger footwell. Car suddenly lost power as I was pulling out and lit up like a Christmas tree. Check engine, 4lo and trac off. I got the battery disconnected right away and towed home. It’s been sitting for a couple days with the battery out. Should I let it dry some more before trying again?

 

Corona6, what's the update?

 

So I let it sit for 5 days with the battery unplugged. Might’ve been overkill but I wanted to give it enough time to dry out. Plugged it back in this morning and it started right up! No codes and all the electronics seem to be working fine. May take it to my Indy shop this week to get the moonroof drains cleared.

 

That's great man, good to hear.

 

Have you tried checking them out yourself?

 

I know how to clean/vacuum the front two drain holes, but I cannot see holes on the back, anyone know how to clean the drain holes on the back of roof?

 

Update:

Sorry, I swear I posted this, but I guess not.

I had to take it into my friendly local Lexus garage who replaced the ECM, and clean out the drains. Long story short, the drains were not as clean as I thought they were, I went through a high-powered car wash, the water tried to drain, but couldn't through the intended route, and ended up dripping down through the cabin, destroying the ECM as it went. One new ECM and a large chunk of my paycheck and things are now back to normal.

 

"Try a different car wash"...the tech is clueless...
I currently own three GXs (a 16, 21 and 23--actually had two 16s) and never had any carwash/sunroof issue until I got my 23. Thought I felt a drop on my head while going through the blow dryer segment, the first time I took it through the touchless car wash. Next time, same thing. Stuck my finger between the sunroof and headliner, felt wetness in the frame of the sunroof. Looked at the outside roofs of my other GXs, and found that the rear of the sunroofs were all a fraction of an inch higher than my 23. I was going to take it to my dealer, but thought I would check out the CL forum first--found nothing except this post. Looked at Youtube yesterday. You guessed it, I found a video of a guy demonstrating the easy adjustment of the sunroof. All you need is a Torx 25 bit, and in about 5-10 minutes, and you can make the adjustment!

 

how to avoid the leaking? clean four drain holes every year, and change the rubber seal rim of the glass?

 

I doubt that after 900 miles my 23 has clogged drain holes.