Rx400h 2005 sunroof not working

Scooby2a · July 16, 2023

Hi all. Any ideas or to point me in the right direction in self diagnosing my sunroof issue. The sunroof buttons do nothing and the fuses are all ok. I've seen endless videos but most are about the sunroofs being stuck or not tilting when they should etc. Also the seat memory buttons have also stopped working.

Its been like this for 3 years and only reason I'm reaching out for advise is because the sunroof has dropped slightly and I'm worried about water making its way in now.

It's a rx400h 2005 model.

katabrontes · July 16, 2023

It sounds like a reset problem if the seats are affected as well. My sunroof failed soon after we bought our 2006 RX350. The motor had burned out and the caused was traced, eventually, to a broken small plastic part which had jammed one side of the mechanism and one of the tapes that move it had broken. It needed the whole assembly to be removed which took about 35 hours of labour. Fortunately covers by the dealers warranty!

Does the handbook have anything about resetting. It seems to be a common problem with the windows and tailgate after the Battery has been disconnected. Maybe worth trying to disconnect the small service Battery and then reset everything according to the handbook.

Scooby2a · July 16, 2023

Hi thanks for replying. The seats do work back\forward etc, only the memory functions don't.

The sunroof buttons are dead like the seat memory buttons. Everything else works which makes me question either

1. They are related or 2. Coincidence that both failed or stopped working.

I have tried the 8 second reset and disconnecting the Battery etc but to no results.

ColinBarber · July 16, 2023

Memory seats are directly linked to the drivers door ECU but that itself is connected to other ECUs via one of the communication buses. Similar for the sunroof. Worth checking all the fuses, not just the one specifically for the sunroof such as ECU-B No.1, ECU-B No.2, ECU-IG No.1, Door No.1, Door No.2, ECU-ACC.

Also you may need to initialise the sunroof - With the ignition switch turned ON,keep the tilt-up or slide close switch pressed.This will enable the sliding roof ECU to start initialising and perform the tilt up, tilt down, open, and close operations of the sliding roof in sequence.

Scooby2a · July 16, 2023

Hi, thanks for this info. I will defo try this after work today and reply with results.

Scooby2a · July 16, 2023

Hi I tried the initialise roof part but had no success. Unfortunately where I am at the moment there is heavy rain so cannot check the fuses you mentioned but will write back soon as I do. Thanks again

Scooby2a · July 20, 2023

Hi again.so I checked all fuses and all are fine. Completely stuck now. Any other ideas?

Scooby2a · July 20, 2023

I Did some digging and removed the centre sunroof console.

The plastic cable is chewed off and cut. Obviously the person that had thebcar before me disconnected the cable hence why no power when pressing the buttons.

So now that I see the problem does anyone know how big or small(fingers crossed, legs crossed,everything crossed) of a job it is?

katabrontes · July 21, 2023

If this is the cable that drives the sunroof it is a big job as you will need to remove the whole sunroof to fix this. I assume this is the same problem as I had and the broken cable was caused by the sunroof jamming and the cable getting overstrained until it snapped. My motor had also burnt out so you may need to replace this as well.

To remove the sunroof you have to remove the headliner and to do this you need to remove the sides as well. It is a big job and the parts are quite expensive.

photo of mine halfway through the job attached.

if you can trace the power supply to the sunroof motor and reconnect the multi plug but isolate this ( or just don't press any sunroof buttons) you might find that the seat memory works again.

Scooby2a · July 21, 2023

Wow that looks like a bang your head against the wall situation. I'm going to have to leave it as is but will try the seats when reattaching the cable in the console.

If the sunroof falls even more is there a way I can manually close it again?

Scooby2a · July 21, 2023

On 7/16/2023 at 12:07 PM, ColinBarber said:

Memory seats are directly linked to the drivers door ECU but that itself is connected to other ECUs via one of the communication buses. Similar for the sunroof. Worth checking all the fuses, not just the one specifically for the sunroof such as ECU-B No.1, ECU-B No.2, ECU-IG No.1, Door No.1, Door No.2, ECU-ACC.

Also you may need to initialise the sunroof - With the ignition switch turned ON,keep the tilt-up or slide close switch pressed.This will enable the sliding roof ECU to start initialising and perform the tilt up, tilt down, open, and close operations of the sliding roof in sequence.

2 hours ago, katabrontes said:

If this is the cable that drives the sunroof it is a big job as you will need to remove the whole sunroof to fix this. I assume this is the same problem as I had and the broken cable was caused by the sunroof jamming and the cable getting overstrained until it snapped. My motor had also burnt out so you may need to replace this as well.

To remove the sunroof you have to remove the headliner and to do this you need to remove the sides as well. It is a big job and the parts are quite expensive.

photo of mine halfway through the job attached.

if you can trace the power supply to the sunroof motor and reconnect the multi plug but isolate this ( or just don't press any sunroof buttons) you might find that the seat memory works again.

How long did this take ?

katabrontes · July 22, 2023

About 35 hours of labour by the dealer who sold it to me.

katabrontes · July 22, 2023

I think you can close the sunroof with a mechanical crank via a hex socket on the gearbox. As I recall the key is clipped under the cover plate for the mechanism

Spock66 · July 22, 2023

I think it would be a poor design if there was not a manual over-ride option, maybe this is detailed in the service manual?

Scooby2a · July 23, 2023

On 7/22/2023 at 11:31 AM, katabrontes said:

I think you can close the sunroof with a mechanical crank via a hex socket on the gearbox. As I recall the key is clipped under the cover plate for the mechanism

Will have a go when it's dry. Thank you for helping out

hughseh · July 23, 2023

On 7/22/2023 at 11:31 AM, katabrontes said:

I think you can close the sunroof with a mechanical crank via a hex socket on the gearbox. As I recall the key is clipped under the cover plate for the mechanism

Hi, would you mind adding some more detail on this as I have a similar fault and just need the roof shut manually.

1. The gearbox to the sunroof? Where is that exactly?

2. what key and what does this do?

Thanks

ColinBarber · July 24, 2023

On 7/22/2023 at 11:31 AM, katabrontes said:

I think you can close the sunroof with a mechanical crank via a hex socket on the gearbox. As I recall the key is clipped under the cover plate for the mechanism

I'm not aware of any manual override on the RX series II sunroof. The gearbox doesn't have anyway to manually turn it.

https://www.ebay.co.uk/itm/233753016871

katabrontes · July 24, 2023

I might have been thinking about my old Toyota Surf when referring to this manual override to close the sunroof. If so apologies for raising your hopes.

However given that both are made by the same company and many (? most) parts are shared between Lexus and Toyota it does seem odd that the same system isn't common to all Toyota/Lexus sunroofs. Clearly failure is inevitable from time to time and an open sunroof is a pretty serious problem.

Scooby2a · July 24, 2023

1 hour ago, katabrontes said:

I might have been thinking about my old Toyota Surf when referring to this manual override to close the sunroof. If so apologies for raising your hopes.

However given that both are made by the same company and many (? most) parts are shared between Lexus and Toyota it does seem odd that the same system isn't common to all Toyota/Lexus sunroofs. Clearly failure is inevitable from time to time and an open sunroof is a pretty serious problem.

Yeah it doesn't make sense if there isn't a way to manually close. Toyota are pioneers and not having a "back door" kinda doesn't make sense.

Perhaps someone else has had a similar experience?