Power Back Door (Tailgate) not working on 2010 (Series 3) RX450h

[Spacewagon52]

58 minutes ago, GSLV6 said:

Thought I'd update this thread since self diagnosing the issue and finding Lexus service team were wrong to quote me for a new Power module and ECU for the rear door.

For anyone suffering similar issues, the culprit all along is likely to be the auxiliary battery.  Unless its charged on recover mode at 4 amps or less, it'll not properly recover, and permanent damage is likely of it dips to under 50% capacity/charge.  Trouble is, most battery chargers just tell you it's charged so you have to buy a battery checker (mine coast me £30) which tells you the charge capacity as well.  No expensive parts replacement needed.

It transpires that the battery needed a full week on trickle using the agm mode on my CTEK.  Lexus supposedly checked it but obviously not the current charge capacity!  Once recovered, the tailgate and rear power module worked absolutely fine....oh, up until today when I went to start the car and got nothing as the battery finally died on me (which I was expecting).  Anyone know of a drop in agm replacement 220long x 180 wide x 180 to 200 tall?  I can't find one for love nor money!

Auxiliary Battery can cause so many issues when it is not fully charged. First thing to check in future for any electrical issues.

[Vadim]

1 hour ago, GSLV6 said:

...

For anyone suffering similar issues, the culprit all along is likely to be the auxiliary battery.  Unless its charged on recover mode at 4 amps or less, it'll not properly recover, and permanent damage is likely of it dips to under 50% capacity/charge. 

...

It transpires that the battery needed a full week on trickle using the agm mode on my CTEK.  Lexus supposedly checked it but obviously not the current charge capacity!  Once recovered, the tailgate and rear power module worked absolutely fine....oh, up until today when I went to start the car and got nothing as the battery finally died on me (which I was expecting).  Anyone know of a drop in agm replacement 220long x 180 wide x 180 to 200 tall?  I can't find one for love nor money!

Hi, the undercharged Battery is definitely correlated somehow to the PBD issue, but it does not seem to be the answer either. In my case, I replaced the Battery, and it did not help: the PBD started working on its own 3 months later.

As per the Battery, there is a separate thread for that:

The original is Panasonic AGM 55D23L (you can try Toyota / Lexus / Subaru dealers for the best price). If you want to exercise your judgement and consider non-AGM batteries, there are plenty by the same code for a fraction of a price.

[Vadim]

A few photos of the troubled PBD ECU for reference.

[Vadim]

Unfortunately, there are no traces of batteries or capacitors for memory keeping, which could explain the PBD failure in ageing or long underpowered units.

[steveledzep]

12 minutes ago, Vadim said:

A few photos of the troubled PBD ECU for reference.

Wow, that looks really complicated.  My PBD failed last December and I replaced the aux Battery in January.  Like you Vadim, my PBD didn't start working again until 3 months later in April.  This resurrection of the PBD occurred after a lengthy dry spell of weather.  This got me thinking and I noticed the roof rail mounting is immediately above the ecu and motor assembly.  I can't say if it was damp affecting the ecu, but I removed the rail mounting bolts and used copious amounts of Plumbers Mate when refitting.  It certainly won't do any harm and may just avoid failure from water ingress in the future.

[GSLV6]

I'm pretty convinced (in my case) it was 100% related to the auxiliary Battery.  Despite Lexus saying that they checked the PBD module and that "it had failed" and was "most definitely dead"  quite obviously it didn't and it wasn't.  The current draw is quite high for the tailgate motor and it draws a fair amount for a fair time so if the aux Battery isn't healthy enough, part of that circuit will have a voltage drop sensor so rather than damage anything, it will cut out, which is what happened in my case.  Recovering the Battery demonstrated that but given that Vadim changed his Battery then it does appear that some of the SM components have failed

I had something similar happen on an old electronic fuel injection module which had entrapped moisture causing issues and used to heat it with a hair dryer to get my bike started!  Whilst I work with electronics, it's in the audio world but there are some common failure symptoms and mechanisms.  'Lytic caps can increase in ESR and drift with age and heat and throw circuits out of kilter but the likely cause with these SM boards is usually in hyper sensitive components like SM fets and the like.  They only need to be knocked and they fail.  Unfortunately, such miniaturisation necessarily means that when such things happen, discrete repairs become largely impossible and the whole board needs swapping out, usually at ££££'s for pennies worth of components. 

 

 

[Mr Simon BELL]

Afternoon. Hopefully someone can assist with the power tailgate not working whatsoever on my 2009 RX450h. Fails to open on fob or by switch within car. Also no beeping or any sound at all when pressing with fob or button in car. 
Went to Lexus who believe that the motor is defective and that this is common on this model estimated cost of supply and fit £1550 

However, seen this thread and there’s mention of recent issues with replacement batteries. Lexus replaced my defective 12v service Battery a few weeks ago. And to be frank Im not sure that I’ve actually ever opened or used the rear boot and the tailgate since. Not needed to. 
 

Lexus showed me how to open rear tailgate from within the car, but this is hardly practical. More importantly is that all the boot internal curtesy lights don’t work and nor does the 12v cigarette point. Within the boot. 
Lexus say that tailgate lift motor defective and that this shorts out other circuits powered via the unit. 

Help!

Thanks. Simon.  

[RonsonSJohnson]

Quick one on this topic, would replacing the rear struts before they fail help extended the motor life.

I am thinking thr extra strain to open back door weight if the struts don't lift as well.

Any opinions on a preemptive bit of maintance ?

[Tedo]

my problem started when the 12v Battery failed during lockdown, during a very wet time.(I understand there were several cases at that time). 're setting did not clear the problem . I believe that water /damp affected the motors circuit board, which was exposed to climate. Water may have penetrated through the bolt hole on the left side holding the back door hinge. There is no cover to the circuit board. Lexus claim the motor failed, but the problem was intermittent. I believe it is a design fault.

I changed the car.

[Vadim]

On 5/16/2021 at 7:31 PM, GSLV6 said:

Thought I'd update this thread since self diagnosing the issue and finding Lexus service team were wrong to quote me for a new Power module and ECU for the rear door.

For anyone suffering similar issues, the culprit all along is likely to be the auxiliary battery.  Unless its charged on recover mode at 4 amps or less, it'll not properly recover, and permanent damage is likely of it dips to under 50% capacity/charge.  Trouble is, most battery chargers just tell you it's charged so you have to buy a battery checker (mine coast me £30) which tells you the charge capacity as well.  No expensive parts replacement needed.

It transpires that the battery needed a full week on trickle using the agm mode on my CTEK.  Lexus supposedly checked it but obviously not the current charge capacity!  Once recovered, the tailgate and rear power module worked absolutely fine....oh, up until today when I went to start the car and got nothing as the battery finally died on me (which I was expecting).  Anyone know of a drop in agm replacement 220long x 180 wide x 180 to 200 tall?  I can't find one for love nor money!

Keeping the Battery charged definitely helps, but in my case the PBD did not work even after Battery replacement.

 Then it suddenly started working again after two months.

The PBD circuit board shows no signs of any batteries or supercapacitors, which could be used for memory keeping and would be subject to Battery voltage issues. So the only thing to blame appears to be the ageing chips or other elements of the PBD. Unfortunately, this module is so specific, that no ECU specialists can diagnose it, let alone repair.

[Vadim]

On 10/16/2021 at 9:27 PM, RonsonSJohnson said:

Quick one on this topic, would replacing the rear struts before they fail help extended the motor life.

I am thinking thr extra strain to open back door weight if the struts don't lift as well.

Any opinions on a preemptive bit of maintance ?

I doubt that, as the motor and mechanics are rarely the issue. The problem comes from the PBD circuit board.

[Martin52]

On 2/11/2021 at 1:30 AM, Herbie said:

That's the 'manual' button. You use that if there's a problem with the electrics and use good old elbow grease to lift and lower the tailgate yourself.

Hello, my name is Martin from the Netherlands.. I have the same problem with the not functioning knob under the plate, but I don't think it's just an override.... In a Youtube movie I saw a man opening the tailgate of a RX350 open by shortpressing the knob to open the gate automaticly. In this little video you can see, how it should work according to me, from minute 13:13, at 14:00

Thank you, I hope there is something like a software reset to solve this. I don't believe, it's only a manual override button....

[Vadim]

Martin, thanks for the video.

I would also recommend to remove the passenger’s ceiling handle (just two metal clips there).

Having two pretty assistants as on the video definitely helps )

[Vadim]

I think for the most of the cases discussed in this topic we had absolutely no reaction from the PBD unit, not even a beep, with Central ECU stating “no connection”. And the key inconvenience was that you could not open the boot from outside (the PBD controls the tail gate lock as well).

On the video it beeps and opens manually, which suggests that the PBD ECU is functional and there is a different kind of issue. I suspect the mechanical part was broken or the PBD was simply not initialised after Battery disconnection.

[Anjokay]

Hi Herbie,

I'm having problems opening and closing my tailgate. I opened it with the fob this morning but to my surprise the gate refused to lock back so I hard to force it to close and ever since  then I've tried couple of times to reopen it but there was no joy. There is always a beep sounds each time I attempt to open it. Please I need informatiom to resolve this problem.

Cheers Kay.

[Herbie]

43 minutes ago, Anjokay said:

Hi Herbie,

I'm having problems opening and closing my tailgate. I opened it with the fob this morning but to my surprise the gate refused to lock back so I hard to force it to close and ever since  then I've tried couple of times to reopen it but there was no joy. There is always a beep sounds each time I attempt to open it. Please I need informatiom to resolve this problem.

Cheers Kay.

Hiya Kay, just sent you a PM that may help you.

[Anjokay]

Quote

Thanks Herbie.

 

 

[Herbie]

You're welcome 

[RonsonSJohnson]

would anyone have the part numbers for the 2 gas structs for the gen 3 2012 rx450h,

i am going to replace as a precaution,

any extra stress on the mechanics of the door is not good and full functioning structs would help for a cheap outlay.

[j8pfc]

Lexus parts direct sell them

https://lexuspartsdirect.co.uk/parts/lexus-rx/lexus-rx-phase-iii-2009-2015/lexus-rx-3-exterior-interior/lexus-rx-phase-3-o-s-boot-strut-2/

They also have the near side listed as well..!!!

Not cheap 🤬🤬

Others have used the struts from SGS Engineering

https://www.sgs-engineering.com/gsc2953-lexus-rx450h-boot-strut

Check the forum for fitting advice on SGS struts…

[PMcH]

Hi Herbie, I’m having same problem, tailgate won’t open but I can hear a click when I press the external button, no lights in boot when I open it manually. Can u send me on the info you have pls. Tks Padraig 

[Herbie]

42 minutes ago, PMcH said:

Hi Herbie, I’m having same problem, tailgate won’t open but I can hear a click when I press the external button, no lights in boot when I open it manually. Can u send me on the info you have pls. Tks Padraig 

Just sent you a PM mate.

[PMcH]

Tks a mil Herbie 👍👍

[Spottedlaurel]

Interesting (and saddening) to see we're getting enquiries about this one again. Is it related to the onset of cold, damp weather?

[ColinBarber]

4 hours ago, Spottedlaurel said:

Interesting (and saddening) to see we're getting enquiries about this one again. Is it related to the onset of cold, damp weather?

Yes almost certainly