RX450h tailgate woes again

[GSLV6]

I wonder if anyone else has had a similar issue and if so, what the remedy was?

about 14 months back, the tailgate wouldn't operate on the button and even if manually opened from the inside lever, wouldn't properly shut.  The electrics operating the motor and lock seemed to have failed and when I contacted Lexus, their reply was "sounds like the rear power pack has failed".  I wasn't so sure is the failure coincided with the auxiliary Battery going flat as the car hadn't had enough use.  I connected it to a CTEK charger and put it in Battery reconditioning mode and left it for two days and hey presto, all was good again.  The Battery seemed to be holding charge and itself was only 2 years old, replacing the original (the car's a 2014 model).  No problems since until just after the recent cold snap.  I noticed that when at a supermarket a few days ago, the tailgate was slow to close and I suspected that the auxiliary Battery might be low on charge, making a mental note to charge it over Christmas.  Anyway, yesterday when wanting to open the tailgate manually, it wouldn't open and showed no signs of life.  Rear lights, indicators and wiper work fine.  I manually opened the tailgate using the manual lever in the boot and hooked up the Battery charger, again setting it to recovery mode and sure enough the Battery seemed quite flat, but thankfully took a charge and this morning the green light on the CTEK confirmed it was charged.  I tested it withy a multimeter and got 14.7 volts with engine running and 12.7 volts with engine turned off although this voltage very slowly dropped over a few minutes by a little (perhaps 0.2 volts).  I tried the tailgate but no joy.  The electrical feed seems dead.  Given that the Battery should have enough charge to open and close it this leaves two options.  One is the rear powerpack itself and perhaps if I'm lucky the ecu may just want reflashing (I had this on my GS300 where the same thing happened and the boot wouldn't close and I was told that it needed an ECU reflash which solved the problem).

Lexus say it's most likely the power pack still and (gulp) a replacement is £1000!

Has anyone perhaps had the same thing happen and if so, did you have to replace the power pack or is there a chance that a low auxiliary Battery has upset the ECU and thrown a fault which locks out the power pack from engaging?

[katabrontes]

Oh dear!  Makes me quite pleased I am hanging on to my 2006 350.  I will need to replace it eventually but these sort of problems with hybrids are worrying.  I thought the 450 had solved the auxiliary Battery problems which seemed to be quite common with the 400 series.

[Spock66]

1 hour ago, GSLV6 said:

Lexus say it's most likely the power pack still and (gulp) a replacement is £1000!

I'd suggest changing the auxiliary Battery first, relatively cheap and a good idea to replace anyway.

Power pack is that the Hybrid Battery?

If it's the main Hybrid Battery that should be covered by Lexus warranty if you have kept the dealer service history up to date.

[08ISF]

£1000 for the power pack. Won't Relax cover it then? Don't see why not.

[GSLV6]

Apparently there are two power packs.  One looks after central locking for the main doors and powers the windows.  The second is purely for the tailgate and is a higher torque motor with associated power supply.  These are all driven off the 12v system.  The change to Lexus warranties might cover it as long as your car is serviced by Lexus, which mine always has been.  Last year, they included work within the service warranty at service time which otherwise could have set me back over £700 so its a no brainer to keep any Lexus car serviced by them.  I use Cheltenham and they've always been very good with me.  I use independent for MOTs as there's no sense in a 50 mile round trip for an MOT but on reflection had I had the car MOT'd (which was last week) with them, they may have picked up on this and a split bushing and done the repairs under warranty anyway. Hindsight is a wonderful thing.

Struggling to find a source for a modestly priced auxiliary Battery as it's an odd size.  Anyone happen to ave a link?

[Mr Vlad]

If your 12v Battery is only 2 years old and losing charge then there's either a power drain happening or the Battery is knackered but should be within its own guarantee. 

I'd start with finding an auto sparky to run tests on power drains.

[GSLV6]

Well, I think I have my answer.  Whilst checking charger settings, I noticed I didn't have it set for AGM so decided to disconnect the charger as it was showing fully charged, and try the reset by disconnecting the negative Battery terminal for 10 seconds, reconnecting then re-initialising by closing the tailgate fully.  Et Voila...the tailgate operated manually again (but not on power) and boot courtesy lights came on.  That would indicate a Battery issue.  Sure enough, when reconnecting the charger, this time setting it to AGM mode, instead of rapidly rising to almost fully charged, it stuck mid way up the charging cycle which would indicate to me a Battery issue.  Last time this happened I got away with a Battery charge but a few months later ended up having to replace the Battery after the problem re-occurred and didn't have any problems up until now, so I'm almost certain this is a Battery condition fault. I'll replace the Battery and see if that does the trick.  It's expensive at Lexus but at least it's cheaper than a new ECU or power module.  Moral of the story is unless run for 30 minutes or more regularly, and especially in cold weather, these batteries take a hammering and need really to be hooked up to a conditioner when not in use.  I'll report back when I have changed the Battery but fingers crossed, this will be the solution.  It's my third Battery in 6 years!

[Herbie]

1 hour ago, GSLV6 said:

Apparently there are two power packs.  One looks after central locking for the main doors and powers the windows.  The second is purely for the tailgate and is a higher torque motor with associated power supply.  These are all driven off the 12v system.

Either you're getting your terminology wrong or you're getting wrong information because that just doesn't make any sense.

A power pack is a Battery (such as the jump start power packs) and there are definitely no power packs in the car apart from the 12V Battery, the high voltage traction Battery, and a small back-up Battery for the alarm system.

I'm assuming you mean ECUs, not power packs, in which case that would indeed make more sense. If you read back through the topic it seems to be that the tailgate ECU does suffer from low temperatures and dampness and, in worst case scenario's, needs to be replaced.

[GSLV6]

Yes, quite right...I meant the ECU not what was supplying it.  I'm pretty sure it's an auxiliary Battery issue having tested it.  Insufficient current despite being charged.  Had exacly the same thing a few years ago and a change of Battery sorted the issue so will replace the Battery which is probably due replacement about now.  The recent cold snap probably pushed it over the edge but it's not showing anything like  enough residual current on the tester.  Once these batteries drop to below 50% it's difficult to recover them.  I did try with the recovery mode on the charger but unfortunately it still hasn't done the trick.

[GSLV6]

Thought that I'd post an update after finding the fault.  I tried every trick but the rear door failed to work despite multiple re-sets, charging the auxiliary Battery, checking wiring and connections.  Left it with Listers Lexus in Cheltenham who've seen this issue with quite a few 450h's and they were brilliant.  They stripped the rear tailgate panels, removed the roof headlining,checked the ECU and Canbus system and wiring, ran fault code readers and finally discovered that the rear motor unit had failed prematurely, not uncommon it seems.  The car was with them 3 days and during that time they gave me the keys to a brand new UX250h (which by the way was brilliant...the best driving Lexus I've had the pleasure of using since my old GS300 V6).

The motor was replaced, the headlining and panels all replaced faultlessly and the car washed and vacuumed inside.  They then had someone drive the 30 minute trip to where I live and drop it off.

Charge?  I was expecting to pay £1000 plus.  The damage for the work was nothing, zip.  I was only charged £15 for the insurance cover on the UX.  They classed it as a warranty claim and returned the car in perfect working order.  Now that's why my next car will be a Lexus, they really do look after their customers.

[royoftherovers]

21 minutes ago, GSLV6 said:

Thought that I'd post an update after finding the fault.  I tried every trick but the rear door failed to work despite multiple re-sets, charging the auxiliary battery, checking wiring and connections.  Left it with Listers Lexus in Cheltenham who've seen this issue with quite a few 450h's and they were brilliant.  They stripped the rear tailgate panels, removed the roof headlining,checked the ECU and Canbus system and wiring, ran fault code readers and finally discovered that the rear motor unit had failed prematurely, not uncommon it seems.  The car was with them 3 days and during that time they gave me the keys to a brand new UX250h (which by the way was brilliant...the best driving Lexus I've had the pleasure of using since my old GS300 V6).

The motor was replaced, the headlining and panels all replaced faultlessly and the car washed and vacuumed inside.  They then had someone drive the 30 minute trip to where I live and drop it off.

Charge?  I was expecting to pay £1000 plus.  The damage for the work was nothing, zip.  I was only charged £15 for the insurance cover on the UX.  They classed it as a warranty claim and returned the car in perfect working order.  Now that's why my next car will be a Lexus, they really do look after their customers.

A great posting Paul, thanks.

Some lexus Dealerships do and some don`t !

I`ve written to Lexus Customer Services 3times since Jan 1, without even an acknowledgement !

[GSLV6]

59 minutes ago, royoftherovers said:

A great posting Paul, thanks.

Some lexus Dealerships do and some don`t !

I`ve written to Lexus Customer Services 3times since Jan 1, without even an acknowledgement !

Sorry to hear that John.  Which franchise out of interest was that?

[royoftherovers]

2 hours ago, GSLV6 said:

Sorry to hear that John.  Which franchise out of interest was that?

I bought the NX from Liverpool but they have been fine.

It is Lexus Customer Services that has not responded to  my emails concerning the absence of an official complete Handbook for a Septuagenarian to read on a vehicle that could cost up to circa £50k !

[GSLV6]

4 hours ago, royoftherovers said:

I bought the NX from Liverpool but they have been fine.

It is Lexus Customer Services that has not responded to  my emails concerning the absence of an official complete Handbook for a Septuagenarian to read on a vehicle that could cost up to circa £50k !

Surely the dealer supplying the vehicle should ensure that's included?  Or is it that they (Lexus)don't routinely supply a full owners' manual any longer?

[royoftherovers]

10 minutes ago, GSLV6 said:

Surely the dealer supplying the vehicle should ensure that's included?  Or is it that they (Lexus)don't routinely supply a full owners' manual any longer?

The latter, I think Paul. Do they care about the customer any more or is the objective to sell the vehicle and receive revenue ?

[GSLV6]

18 minutes ago, royoftherovers said:

The latter, I think Paul. Do they care about the customer any more or is the objective to sell the vehicle and receive revenue ?

Supply and demand rules but they'll start driving people away from Lexus and onto other marques if they continue chipping away like this given that the playing field for hybrids and EVs for example has become more level in terms of reliability.  People need value and there's no sense in charging what they do for a premium hybrid or EV without an owner's handbook, so my guess is they'll lose out on what is after all something that costs them very little in the scheme of things, particularly at their premium prices.

[Dave450h]

On 1/26/2023 at 11:29 AM, GSLV6 said:

Thought that I'd post an update after finding the fault.  I tried every trick but the rear door failed to work despite multiple re-sets, charging the auxiliary battery, checking wiring and connections.  Left it with Listers Lexus in Cheltenham who've seen this issue with quite a few 450h's and they were brilliant.  They stripped the rear tailgate panels, removed the roof headlining,checked the ECU and Canbus system and wiring, ran fault code readers and finally discovered that the rear motor unit had failed prematurely, not uncommon it seems.  The car was with them 3 days and during that time they gave me the keys to a brand new UX250h (which by the way was brilliant...the best driving Lexus I've had the pleasure of using since my old GS300 V6).

The motor was replaced, the headlining and panels all replaced faultlessly and the car washed and vacuumed inside.  They then had someone drive the 30 minute trip to where I live and drop it off.

Charge?  I was expecting to pay £1000 plus.  The damage for the work was nothing, zip.  I was only charged £15 for the insurance cover on the UX.  They classed it as a warranty claim and returned the car in perfect working order.  Now that's why my next car will be a Lexus, they really do look after their customers.

I have a similar problem on my 2010 RX450 (100k) , I am suspecting my PBD motor has failed due to water /damp damage, possibly due to water ingress through the roof rails, does you car have roof rails ?

Also I live in Cheltenham but haven't been to Listers yet. I think I will get them to service the car but might end up replacing this PBD unit myself as I have no warranty. 

 

[GSLV6]

Yes, mine has roof rails but they didn't mention if it was water ingress, just that the motor unit had to be replaced. If you're covered by Lister's extended warranty, they should cover it unless being over 10 yrs old excludes it (I think some parts are covered for 10 years only).