RX400 electrical problems ???

[GillJ]

I have an 06 RX400 which started developing Battery issues, i.e. after 4 - 5 days of non use Battery was dead, had it tested and was faulty so new one purchased. Same issue continued and after investigation by auto-electrician it was discovered there was quite a large Battery drain when car just parked. Was eventually traced to one particular circuit (fuse box in engine compartment) and when that fuse pulled drain stops. As a short term measure that fuse has been routed through an external switch so when car parked and locked, switch flicked and Battery fine. I know this fuse operates the central locking and when car is started the on board computer figures for speed, mpg etc are at Zero and heater/air-con is switched to Off. Cannot discover what else if anything is on that fuse or which particular circuit is at fault. Would putting on a Lexus dealership computer system be able to investigate right down to where fault is? Added to this when I started car yesterday & today the switches on the door only operate the drivers window (others work independently and have even tried reset but no success), the mirrors do not adjust or fold, the seat memory system is dead, power boot won't operate and strangely the warning light for showing lights on doesn't illuminate?. I also have the dreaded Check Hybrid & Check VSC messages and symbols. The car actually drives perfectly round the block and everything else electrical seems to work fine. Anyone able to tell if all these could be connected/related, I have 2,3 or even 4 separate issues. If another fuse has blown which one and where is it???

Sorry for such a long post, thanks to all who survived to the end and believe me if I could have condensed it I would :-)

[Haylands]

Most of those are probably down to low voltage, your battery may have been close to dying anyway and a few discharges have finished it off...

Dealers will have some hardware to plug in that will measure voltage use so they should be able to get to the bottom of it, having said that most auto electricians should be able to isolate the exact drain from a multi use fuse...

[GillJ]

It is a brand new Battery only fitted 3-4 weeks ago and is fully charged, may look for a specialist garage in Dundee (unless anyone can recommend someone local to me) and get second diagnosis.

[Haylands]

Could try disconnecting the Battery and reconnect, sometimes resets things...

[GillJ]

Tried that as well Pete, fully charged Battery last night while disconnected?

[Haylands]

Hopefully a dealer can wave his magic wand at it, it always seems to me if you get loads of issues like that it's something little or reprogrammable...

Fingers crossed....

[GillJ]

Hopefully will be something like that, nearest Lexus dealership 60+ miles away so not convenient but do have Toyota dealership about 5 mins away although they don't seem keen to look at it and even say Lexus loath to tell them anything anyway.

[yuen321]

Hi Gill,

The Battery issues may be caused by old rusted Battery Negative cable's chassis connection which located deep under the Battery tray.

 

 

[GillJ]

All cables connecting to Battery and ground points were fully cleaned etc when Battery replaced so hopefully they are OK. If it was a bad ground would it not perhaps causes issues with all electrical items. Spoke to another auto electrician yesterday who said he thinks there is an ECU in the drivers door which controls most (if not all the problem items) and it maybe that has bad connections or is failing. Can only tell once he gets car in and strips door out.

[yuen321]

Bad ground at Battery side will caused alot electricals problem or damage. The electrical items will act like fuses to the Battery when resistance build up at the battery's cable connection.

A body ECU control all doors lock/unlock  near the glove box. 

[GillJ]

Booked into Lexus dealership next week so let's see what they turn up. Car smells damp inside (apparently independent source advises me) and windows fog up heavily when car sitting so could be a water ingress related issue.

[GillJ]

Update on this issue at last, main dealership have established water ingress from sun roof and water ended up all over loom connections behind glovebox, numerous pins/sockets eith covered in green corrosion or badly covered in blackish carbon deposit from arcing. All electrics cleaned up and issues with sun roof leak resolved. Everything now working correctly so will find out tomorrow when I pick up car.

[Farqui]

Excellent, its always to good to get to the bottom of an issue. Fingers crossed that it's sorted now eh.

[Toby388]

I have the same problems GilJ. After considerable searching it’s reassuring to find someone who has experienced the same issues on an RX400; Hybrid/VSC warnings, no ring mirror, seat memory, and also warnings on doors being open when they are closed. Might I ask if the repairs behind the glovebox did the job or were there further problems? I realise it was sometime ago now...

[ColinBarber]

3 hours ago, Toby388 said:

I have the same problems GilJ. After considerable searching it’s reassuring to find someone who has experienced the same issues on an RX400; Hybrid/VSC warnings, no ring mirror, seat memory, and also warnings on doors being open when they are closed. Might I ask if the repairs behind the glovebox did the job or were there further problems? I realise it was sometime ago now...

First thing to check is your 12v aux Battery. If it is partially discharged you can get all sorts of errors.

If you have a sunroof then make sure the drain holes are clear. Open the roof and pour some water in the channel, it should run out under the vehicle on both sides.

[hughseh]

Just wanting to bump this thread as it seems to be a very specific set of issues that I'm also experiencing. It's not a random set of issues, but always the same set, namely

Tailgate won't work from fob or button on dash

Sunroof won't work at all

Side mirrors won't operate at all

Memory seats not working

Electric windows only work from the window you're operating (i.e. the drivers side control can only operate its own windows).

 

Noting the responses above, it seems to be corroded wiring behind the dash or I've read elsewhere corrosion to the ECU, but have pulled off the lower dash to both sides, I could not locate any corrosion to connections in the slightest.

 

I do have the P0AA6 code (water ingress to hybrid battery), but it seems unrelated to that given others experience 

 

Edit: just read another post where someone cleared the same issue by changing his brake pads, which were worn.

My full list of fault codes

P0AA6

U0146

C1259

C1310

B1214

 

[Bluemarlin]

Have you checked to see if there actually has been water ingress to the hybrid Battery? It's not uncommon if your sunroof drains have been blocked, or water has got in via a number of areas that can leak.

If you have had a leak and water has got to the wiring, it's quite possible that wires could be corroded even though you can't see the extent of it. The water can wick up the wires and corrode inside the insulation, I've seen corrosion several feet inside the insulation on boat wiring.

Here's a couple of videos on leaks in the RX 400h that you might find helpful:

 

[hughseh]

1 hour ago, Bluemarlin said:

Have you checked to see if there actually has been water ingress to the hybrid battery? It's not uncommon if your sunroof drains have been blocked, or water has got in via a number of areas that can leak.

If you have had a leak and water has got to the wiring, it's quite possible that wires could be corroded even though you can't see the extent of it. The water can wick up the wires and corrode inside the insulation, I've seen corrosion several feet inside the insulation on boat wiring.

Here's a couple of videos on leaks in the RX 400h that you might find helpful:

 

Hi, yes, I stripped the carpets the weekend just gone and they were pretty saturated throughout, mainly on the driver's side. Have inspected the sun roof drain on the driver's side with a endoscope and all clear

Tested the door cards and a slight drip that I'll get around to.

 

I also got to the hybrid Battery but didn't remove the covers - the relay, from what I could see had slight corrosion but I've seen photos of much worse. I managed to reach underneath to clear the drain plug, which was blocked.

I've also looked at the various electrical connections behind the glovebox and under the driver's steering wheel panel and no obvious signs of rust / corrosion.

One final point, there is a cut cable on the passenger side underneath the sill trim. I can't see what it would connect to (the cill light is fine). Any ideas, it's a very thin wire, so surely not to do with the hybrid fault 

[hughseh]

A successful update in case it may benefit someone in future. 

I've solved all the electrical problems aside from the hybrid warning in one hit. I don't know how exactly, but I had the car in ready mode and was prodding with the glovebox fuses just now, pulling out the ECU 7.5amp fuse (no.63), then the one next to it. As I reinserted what I think was no.63, it seemed to reset something and I hear lots of pings, etc and look over to see the dash indicator saying the passenger door is open. I've never had that before. Long story short, it's now restored 

Cruise control

Power tailgate (boot) 

Side mirrors adjustment and folding

Dashboard indicator now tells when the lights are on

Vsc warning light has gone 

The only still not working is the sunroof.

 

I have the carpets up in front of the front seats for a few days, drying out. I suspect there must have been some mositure on the fuse or in the system somewhere, that by reinserting the fuse whilst the car was in a ready state has caused a sudden surge that perhaps burnt off some residual mositure or corrosion (I couldn't see any anywhere). That could be bollocks of course. 

 

Now to strip the rear seats out again and get to the hybrid Battery and relay for some repairs with contact cleaner, lol.

Secondary is to fix the multiple leak points, but the good weather recently is giving some breathing space 

[hughseh]

Spoke too soon, just discovered a leak from the radiator this evening (discovered trying to blow hot air onto the cabin floor)

Can't see coolant in the reservoir at all. just hope no permanent damage caused and explains why my fan is always on