LX570 AHC “Basics” - Added as sticky thread for AHC Issues (2 Viewers)

[2001LC]

Actually many Dealership will say don't flush it, you'll damage the system. They may very well say "sorry you messed up". How fat is your wallet $$$, before we replace the AHC system for you. This issue of not running when drained of fluid, IMHO is why many shops say we don't flush the 200 AHC.

But Dealership/shops that say this, are wrong IMO.
Think about it!
Would Toyota engineers design a system that one leak, say in reservoir, which set near ground behind a tire with lines running around undercarriage exposed too road hazards. Allow fluid loss to destroy the system. IDT.SO

That is not what I'd call a third world ready system or off road reliable.

Just letting setting with fluid in reservoir will help, as fluid will settle in. The pump can burn up (my guess) if run dry. So system is refusing to run as a safety. A few start in stop with tech stream and it will work. No Tech stream cable, just start and shut down (key on start, then off and wait) should do the trick. May even need to disconnect battery (reset system DTC) if no results, but it will work.

 

[collexus]

Thanks for all the info in this thread.
One thing the wasn't super clear to me was how much fluid is needed to complete a flush.

I did mine today (2013 LX570 74,000 miles - no towing, no offroading - grocery getter from Kansas).
It took all of 5 liters to complete the flush process.
I put it in Low position, drew off about 1.5L from the the reservoir, then put about 2L back into it.
I bled all 4 corners (draining, then ignition on, letting it raise back to Normal position). It took ~3 bleeds per corner before I was showing clean new fluid. - ~1/3 liter per cycle of Down, close, ignition to raise back up.
I was adding fluid the the reservoir as needed during the process.
.
I was surprised that my old fluid was about black in the tank, and at 3 of the four corners it was a bit cloudy on the first bleed.

 

[2001LC]

How many qt or Liters. As many as it takes.

I've a test. Once clear running after a flush. I drain a little into a white plastic jar. If I see specs in bottom of fluid in the jar, they are 30 micro or large to be seen by naked eye. I keep flushing until none seen. I've a filter system I use once fluid clear. That way I don't waste 5 or 10 good new qts. Lexus just quoted me $36 retail per/qt.

I just had a fellow mud'r (a neighbor) come by with his 10LX more than 100K miles on the clock. His AHC dash warning light came on.

He just had new shock installed. Not likely needing IMHO, but INDY shop replaced for him. He asked for AHC flush and was told it was clean in reservoir so no need to flush.

Well, I found his reservoir dusty and hard to see level. In fact I could not see any in reservoir from hatch. I washed the area and stuck my light on the tire to shin through the reservoir He was a qt low.

So the thinking was; INDY shop looked and thought, "oh not dark" must be okay. DUH the just changed the shocks and likely did not pre-flush or fill those, as they should have. Why did they not top, they said they looked....

@PADDO thought me to pre flush a new OEM AHC shock out of the box. Amassing how dirty brand new shock are internally.
This was a AHC brand new OEM shock out of the box on 2nd or 3rd flushed. I flushed 7 times to get clear.

Here is almost clean for comparison.

IDNY shop likely did not pre fill the shocks, much less pre flush them. So why would they not add some DUUUUUH. The shock they pulled while on a lift (shock fully extended) would have fluid in them that needs replacing. I'll bet they did not replace the seals either.

They said they lube the chassis. I can assure they did not, I looked.

I meant to check if all 9 bleeders cap (5 AHC & 4 brakes) and if brake fluid top properly (they flushed that too). But forgot. Bet they didn't!

I'm working on one now, with no bleeder caps. Two bleeders are frozen in. I'm soaking for second day with penetrating oil. I hope to get them off without breaking the bleeders. A $2 bleeder cap can cost thousands in repairs. I make I've got good rubber bleeders caps on all bleeders. It's important, believe on this.

 

[Emcd]

This is why I only take my LX to Paul. The guy is incredible.

 

[hkeller]

Ok. Where is Paul?

 

[2001LC]

Thanks @Emcd very kind of you to say. About time we flush that AHC again. I don't recall did we flush your transmission? I checked my notes, we just did a 6qt drain and fill.

I'm in Denver! @hkeller

Regards,
Paul.

 

[Emcd]

I’m getting the timing cover leak completed soon under warranty. Let’s sync up after and go through a list on next step. When I get the cover resealed, I’ll get a new radiator, upper and lower hoses and water pump. Figure it makes sense while I’m there. Any dealer recommendations? I moved down south, in the castle pines area.

 

[hkeller]

Damn! Need some AHC help in Virginia.

 

[hkeller]

http://myfirewood.com/LEXUS/LX/rm2452e/PDFs/RepairManual-Suspension.pdf

here is a link to a PDF of the FSM pages (about 1800 of them) for the AHC system.

 

[2001LC]

I’m getting the timing cover leak completed soon under warranty. Let’s sync up after and go through a list on next step. When I get the cover resealed, I’ll get a new radiator, upper and lower hoses and water pump. Figure it makes sense while I’m there. Any dealer recommendations? I moved down south, in the castle pines area.

I didn't see anything going on with your radiator or hoses. I'd hold off and save some $, unless a reason. Your's is so clean I can't think of anything. If you'd like me to look-over before warranty work, I can. Then I may see some stuff. BTW: I R&R thermostat already, so you'll not need.

 

[hkeller]

OK, used TechSteam to find I had an old, inactive code of "C1764 Abnormal Oil pressure due to not opening Leveling Valve." I am going to check the function of all the valves tomorrow with Active Test in TechStream.

Big question I have always had since we got our first LX 20 years ago, does flushing the system (alone with out mechanical work) actually improve the ride?

 

[grinchy]

OK, used TechSteam to find I had an old, inactive code of "C1764 Abnormal Oil pressure due to not opening Leveling Valve." I am going to check the function of all the valves tomorrow with Active Test in TechStream.

Big question I have always had since we got our first LX 20 years ago, does flushing the system (alone with out mechanical work) actually improve the ride?

Sometimes, particularly if the fluid is really old

 

[hkeller]

Only 44K miles on this one. ERRRRR.

 

[grinchy]

It’s been mentioned before but are you sure it has ahc fluid in it?

 

[hkeller]

Not sure of anything at this point. Will do a flush next weekend.

 

[slipkid13]

Paul, where in Denver? Are you a shop or just helping fellow forum members?

 

[2001LC]

Paul, where in Denver? Are you a shop or just helping fellow forum members?

Both. PM sent!

 

[Bradass80]

Both. PM sent!

Please shoot me your info as well. Thanks, Brad

 

[TLCLVR]

LX570 Detailed AHC Bleed Procedure

Ok, figured it was time to contribute something concrete to the group. I'm getting ready to change out my AHC fluid and have been absorbing as much info as I can on the AHC/AVS system from these forums and the tech manuals for a week. There doesn't seem to be a consolidated knowledge bank on AHC in the FAQs, so I took @PADDO's LX470 checklist LX570'ified it, corrected for continental differences (DS doesn't mean the same thing to everyone ), merged it with very useful tips and pics from @longranger, @FinallyGotOne!, @Darb, @2001LC, and many other very helpful Mud user contributions. This is what I came up with.

Calling it a draft for now until the real experts get a chance to look it over, make suggestions and make sure there are no errors. The idea is for it to be detailed enough that anyone can follow along and change their AHC without drama or the need to ask clarifying questions. If it makes the grade perhaps we can convince the moderator to include it in the FAQs. If something like this is already out there somewhere and I missed it... well, call it a labor of love and I guess it was just a good learning exercise for me!

 

[hkeller]

Does anyone have the FSM pages for replacing the accumulators and flushing the system. I was going to do it, but now the wind chill outside this week is going to be under 10 degrees and I don't have a garage, so I am going to get my trusted mechanic to do it.