Nick2020

I’m pleased to report that the fault on the power back door has now been resolved, although I’m still none the wiser as to what caused this failure. I had previously tried disconnecting the power back door lock connecter, then checking the mechanism and switches, but no problems were found. This weekend I took the car on a 20 mile drive to charge up the hybrid and auxiliary batteries, which I had not done since the auxiliary battery had been previously charged. I stopped the car and put it in park, with the ignition still switched on, then tried operating the boot release switch on the dashboard. To my surprise there were two beeps and the power back door opened, so I then closed the power back door using the switch on the tailgate. Next, I tried opening and closing the back door using both the remote and switch above the number plate, which I’m pleased to report are all working now. All I can really put this down to is either a glitch in the ecu, bad connection which cleare whilst driving or the hybrid battery condition low.

Hi Mick, let me know how you get on and I will do the same. I’m hoping to get out to car this weekend to check the lifter motor and ecu, as this seems to control pbd lock mechanism and luggage lights

Hi Herbs, Thanks for the information...this is very detailed and I’m sure it will be extremely useful in helping to diagnose the fault 😀

Hi Ken, I’m glad to hear the switch in the glovebox fixed your problem, I just wish the fault on mine was as simple to resolve. If I get chance at the weekend I’m going to remove the PBD lock assembly, then get the multimeter out to check the motor and switches. I’m thinking that the sequence of operation is that the lock opens first, then the lift motor operates to open the back door. Perhaps the motor / switch has failed or the gearing is out or alignment?

Can anyone help or advise me on a fault that’s developed with the Power Back Door (PBD) on my Lexus RX450h 2010 model. A brief background behind the issue……..The car had not been used for over a month, and the auxiliary 12V battery in the luggage compartment had become flat. I discovered this when I went to open the Power Back Door (PBD), using the remote fob (holding the boot release button for 2.5 secs), it made the usual audible sound but failed to open due to the low battery condition. I disconnected the auxiliary 12V battery and fully charged it, but now the PBD fails to open either via the PBD open / close switch on the dashboard, the external switch on the tailgate or the remote fob. I have carried out some troubleshooting and steps to try and resolve the fault without much success, this included: 1. Checked to make that the main switch to activate the PBD, which is located in the glovebox, is still set to the ON position. 2. Tried performed the initialisation steps detailed in the owners manual (page 90) several times. 3. Disconnected the 12v auxiliary battery for over 30 mins, then tried reconnecting it and performing step 2. 4. After initialising the system several times I have tried to open using either the switch on the dashboard, the external switch on the tailgate or using the remote fob. What I have observed when I try to open the Power Back Door is: 1. There is no audible sound (2 beeps) or indicator flashes when the open/close button is pressed on either the dashboard, the external switch on the tailgate lid or the remote fob. 2. I can’t manually open the tailgate. 3. I’m only able to manually release the back door by removing the small rectangular cover inside the car, then opening it by using the release lever. 4. When the back door is manually opened the 3 x cargo lights in the luggage area do not light up (all the other car interior lights work fine). I have checked the 3 x bulbs, which are all okay and made sure the switch on each light is set in correct ON position. 5. The external buttons on the back door above the number plate, when pressed, open and lock all the other doors on the car, so I'm guessing it could be an issue with PBD lock only. 6. The reversing camera on the tailgate works fine too. The owners manual mentions a fuse in the engine compartment (Type B fuse box - Fuse 9 30A - Power back door system) (see pics), but I can’t see any way to easily remove or check the fuse? Does anyone know where the switch that activates the 3 x cargo lights is located (PBD Lock, lift motor or another location)? Are there any other fuses, relays or other points on the car I should check? Does anyone have detailed information about the operation of the PBD lock and lift motor or a circuit diagram? Any helpful advice or other areas you can suggest to check would be appreciated, as I’m now running out of ideas. Thanks