LX570 climate control woes (1 Viewer)

[Malleus]

This is going to take a minute, so bear with me. This probably has no relation to the same year Land Cruiser.

I've had the truck for 5 or 6 years and have really had to do nothing but drive it in all that time. OK, a few maintenance items, but really very few. A couple of weeks ago I went out to leave for work and had no electrical response. Oddly, I didn't have to unlock the door, something I religiously do. Anyway, I jumped the battery (I finally found a use for a minivan!) and it started immediately.

As soon as I connected the helper battery, the dash lit up. Presumably, the ignition was left on overnight. I could have done it, who knows? Anyway, the dealership had furnished the battery last year and offered to install a new one for the just right price of "have a seat and we'll let you know when we're done".

Fast forward to Saturday morning. I start the truck and the climate controls are dead. I can activate the screen, but no controls respond to input, screen or dash. After a minute (literally), the controls do respond, but the previous settings (temp, auto air, etc) are changed. I'm really OCD and I know exactly how I leave the settings on the entire truck. I reset them and, frustrated, go about my business. Next time I start the truck, same thing. No climate control response until at least 60 seconds. When it does respond, the settings have changed to what I remember them being when I noticed this problem the first time. This has persisted every time I restart the engine.

Here's my question: is there a climate control computer setting that resets to some default, when the battery is disconnected for an extended period of time? This didn't happen the last time the battery was replaced. I'm asking before I dive into the ECU troubleshooting guide.

On a related note, I would appreciate the "secret code" unlocking the on-screen setup menu. I remember seeing it years ago, but never had the occasion to use it. It's something like "turn the lights on and off three times and poke the coners of the screen 8 times, stand on your head, squint with your left eye..."

 

[Malleus]

EDIT: It's a slow Monday, so I decided to do a little fault analysis.

The truck's been sitting in the parking lot for about 3.5 hours. I started it and noticed the same climate control failure. I reset the controls, once they woke up, and turned the engine off. I restarted it immediately and the controls returned to the state they were left in when I shut off the engine. I then performed the same routine, allowing for additional 1 minute intervals. The climate control system started almost immediately, until it didn't.

After 3 minutes, the controls forget to turn on with the engine. I didn't try for 5 minutes yet (it's not that slow here), however, after a 4 minute rest, about 20 seconds after the engine started, the climate system woke up and was set in the state I left it in. I suspect there's a memory (battery) drain somewhere that gets progressively worse as time goes by. I wonder if the climate ECU has a separate (coin) battery?

 

[TeCKis300]

First things first when diagnosing electronics issues.

Since the battery was fully drained (way below it's 50% safe discharge threshold), it's toast. No amount of charging will save it. It's on its last legs and you will have to replace it anyways very shortly.

Resolve the battery issue first, so time to replace it is now.

It's likely that the batt is not delivering enough voltage and current for the A/C system in standby, and it's losing its settings. Sure the batt might start the car for the moment, but the LX is electronics heavy and the batt is potentially also sucking up all the current from the alternator once started and still letting the voltage sag hence the unpredictable behavior.

 

[Malleus]

First things first when diagnosing electronics issues.

Since the battery was fully drained (way below it's 50% safe discharge threshold), it's toast. No amount of charging will save it. It's on its last legs and you will have to replace it anyways very shortly.

Resolve the battery issue first, so time to replace it is now.

It's likely that the batt is not delivering enough voltage and current for the A/C system in standby, and it's losing its settings. Sure the batt might start the car for the moment, but the LX is electronics heavy and the batt is potentially also sucking up all the current from the alternator once started and still letting the voltage sag hence the unpredictable behavior.

The battery was replaced two weeks ago. That was the reason for the post.

 

[NLScooby]

Did the cabin filter get changed recently? I know I experienced some odd behavior with the Climate Control not coming on for at least a minute after the dealer hosed a simple cabin filter install.

 

[KLF]

Have you checked all the fuses? I'm wondering there is a "constant on" circuit that keeps the climate settings (like your clock and radio pre-sets).

 

[Malleus]

Did the cabin filter get changed recently? I know I experienced some odd behavior with the Climate Control not coming on for at least a minute after the dealer hosed a simple cabin filter install.

Odd that you ask. Yes, I did this last week, too. I didn't mention it, because it didn't seem likely it was related.

Any thoughts as to why?

 

[KLF]

There is a baffle that is controlled by the fresh/recirc setting. There's several threads in here about it, I guess something about if you mess with the baffle when swapping the filter it freaks out the system and it shuts down.

 

[Malleus]

There is a baffle that is controlled by the fresh/recirc setting. There's several threads in here about it, I guess something about if you mess with the baffle when swapping the filter it freaks out the system and it shuts down.

Links would be appreciated. I searched and came up empty handed.

 

[electro992]

If the cabin filter was changed without setting the system to recirculate mode first then the blend door could be damaged. This causes the climate control system to reset to default settings every time you start the car. Same thing happens on LS460s:

Blend Door Replacement - Air filter door broken - ClubLexus - Lexus Forum Discussion

 

[blatant]

Did the cabin filter get changed recently? I know I experienced some odd behavior with the Climate Control not coming on for at least a minute after the dealer hosed a simple cabin filter install.

I vote this ^^^

Check here.
LC200 A/C turns off on engine restart

 

[Malleus]

Thanks to everyone who contributed. Problem solved! It was in fact the filter (90° out of position) and a climate ECU fault.

PSA:
My EMVN (whatever that is) had a fault, probably due to my fat fingers not installing the filter properly. Even when I got the filter turned around, I got the same fault (even though I couldn't see it).

So, I lurked into the completely unobvious service menu (turn engine on, hold DISP button and turn the parking lights on/off 3 times), and viola!

What you don't see in this (correct) image is the fault page (sorry, I didn't have my phone at the time). There's a "Memory CHK" (or some such) between the Next Page and Memory CLR if there's a fault. Pressing CLR and then Recheck does what you'd think.

As I said, problem solved. While everyone I've read about had blend door problems (and apparently gave in to the urge to open it by hand, rather than using the RECIRC button), I didn't and couldn't understand why the problem didn't fix itself. So, change your own filter, but pay attention to the orientation (the pleats run side to side) and you won't have the bugginess I had to deal with.

 

[teambell]

Great thread!

 

[NLScooby]

Odd that you ask. Yes, I did this last week, too. I didn't mention it, because it didn't seem likely it was related.

Any thoughts as to why?

I'm glad it worked out! Sorry - I was offline for a bit - or else I would have explained the procedure to replace it as well. In my case, my filter was correctly installed, but the system was likely not put in recirculation mode prior to the install and so the blend door was not properly closed (or seated?). Anyway, I followed someone else's guidance and it worked!

 

[MSLX]

I have to reiterate for the thousandth time...the information on this forum is amazing. Had this exact issue come up several days ago....finally said what the hell and checked on here (I thought no way has anyone dealt with this, I was thinking water ingress issue(s) starting). This thread was perfect and problem solved. The instructions to get into the service menu were spot on. My pleats were running north to south instead of east to west....no recent filter change though. My filter baffle operates as it should. I am missing the cartridge that holds the filter...trying to find one now.

 

[NKP Garage]

great to see you got it fixed. For anyone else running into HVAC issues. First thing you want to do is pull the error codes. Easy to do, no tools necessary. Step by step to pull the codes and also how to reset old stored codes:

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Common issue as some notes is the blend door that shuts over the filter. Common issue on almost all Toyota/Lexus vehicles from untrained technicians. Here's how I fixed mine, but sometimes the fix involves a lot more:
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HVAC Error codes. I'm not sure if this is a full list, but should be most of them:

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Hints from another forum:
*1: If the cabin temperature is approximately -18.6°C (- 3.7°F) or lower, DTC B1411/11 may be output even though the system is normal.
*2: If the check is being performed in a dark place, DTC B1421/21 or B1424/24 (solar sensor circuit abnormal) could be displayed.

 

[bloc]

I am missing the cartridge that holds the filter...trying to find one now.

88899-3A080

 

[MSLX]

88899-3A080

Thank you!!

 

[ARKginger]

So I’ve been experiencing this problem for a bit now. Started randomly, replaced the filter correctly after consulting this thread and that didn’t fix it. Left the rig on the battery charger to see if there was a drain, and that didn’t fix it. I’ve also cleared the codes to no avail. I’ve also checked to blend door to make sure it was moving properly and it was.

This was the most recent code but I don’t see any matches on the table earlier in this thread. Anyone have any suggestions?