I realize this isn't a very helpful reply but one of my trusted shops didn't want to do my fluid because they were worried this would happen, and it was working fine otherwise. I took a chance and did it myself but I'm guessing from their much more experienced point of view it wasn't worth the risk based on having exactly this happen before.
Props to PADDO's AHC fluid replacement method!
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I realize this isn't a very helpful reply but one of my trusted shops didn't want to do my fluid because they were worried this would happen, and it was working fine otherwise. I took a chance and did it myself but I'm guessing from their much more experienced point of view it wasn't worth the risk based on having exactly this happen before.
ramangain
Clarksonian disciple
You created a separate thread about this, so you should remove the duplicate info either posted here or in the new thread.HELP!!! I just did this procedure today while wrapping up baselining a new to me 07 lx. 160k no documented AHC maintenance. Things went more or less fine but now AHC is inoperable!!! I turned the truck on the first time after the left side blead and it took about 2 min or so to go from l to n. Turned it back off to do the passenger side quick bleed and when I got back in the truck it would not go from l to n. Previous to this procedure AHC was working and I had 9 grads with just barely out of spec rear pressures and spot on front pressures. I am at a loss. The pump also seems much louder than usual...
I'm getting this code:
c1751 - Continuous current to compressor motor
I've tried the "bleed air of AHC" in case it is suffering from air lock. The ahc does not seem to respond to this procedure. Since doing the procedure I am also getting the
C1762 - Abnormal Oil Pressure for Pump
and
AHC off flashing even with jumper pins removed from the above procedure
in addition to
c1751 - Continuous current to compressor motor
I'm happy to dig in techstream for some other data if it would help. Sounds like by super bad luck my pump went bad at the exact same time I flushed the fluid but I'm having a hard time believing this...
Having read about every thread I can on this I still have a question @PADDO. I am based in Scotland (cold, rains a lot, funny accent !) and I have a LC200 4.5 turbo diesel 2014 which is I think similar if not identical to the US LX570 suspension wise. I'm due a fluid change and I have two new front accumulators to fit.
Looking at the vehicle I'm not seeing what I expect in that I have two front units and two rear, mounted outboard on chassis rail but no main accumulator only two No.2 gas chambers mounted either side front inboard chassis rail. (see below)
I'm presuming that the bleed process only involves these four bleed points; have I missed or not located yet another bleed point ?
Looking at the vehicle I'm not seeing what I expect in that I have two front units and two rear, mounted outboard on chassis rail but no main accumulator only two No.2 gas chambers mounted either side front inboard chassis rail. (see below)
I'm presuming that the bleed process only involves these four bleed points; have I missed or not located yet another bleed point ?
Going on from above am I looking for a bleed on the Height Control Accumulator mounted inboard centre chassis rail LHS ? (not found but only quick look) see below: ????
There seems to be some odd descriptions in the manual.
We have:
Height Control Accumulator
Centre Cylinder
Suspension Control Pump Accumulator (maybe mounted by the pump ?)
Which one, if any am I looking to bleed ?
Thanks
Or this one ?
OR this one ?
There seems to be some odd descriptions in the manual.
We have:
Height Control Accumulator
Centre Cylinder
Suspension Control Pump Accumulator (maybe mounted by the pump ?)
Which one, if any am I looking to bleed ?
Thanks
Or this one ?
OR this one ?
Might have answered my own question. I've marked up the possible five bleed am I correct ?
Interestingly it as some detail in the text about how this is emptied and refilled on going from L-N and N-H only discharges once a set pressure has been reached.
Interestingly it as some detail in the text about how this is emptied and refilled on going from L-N and N-H only discharges once a set pressure has been reached.
PADDO has not been around in a while. Try posting in the 200
examples:
forum.ih8mud.com
forum.ih8mud.com
Good Luck
Try posting your questions and searching AHC in the 200 series forum. Our AHC system is a bit different in the 100 series.
examples:
LX570 AHC “Basics” - Added as sticky thread for AHC Issues
Point of this thread is to serve as a repository for 200-series AHC info, including LX570 and LC equipped with AHC (in select global markets). Let’s begin with a theory. The 200-series LC (without AHC) and the LX570 (or LC with AHC) are like New York & LA. LC “purists” are like New Yorkers...
forum.ih8mud.com
Search results for query: AHC
forum.ih8mud.com
Good Luck
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thats a good link many thanks very helpfulPADDO has not been around in a while. Try posting in the 200
Try posting your questions and searching AHC in the 200 series forum. Our AHC system is a bit different in the 100 series.
examples:
LX570 AHC “Basics” - Added as sticky thread for AHC Issues
Point of this thread is to serve as a repository for 200-series AHC info, including LX570 and LC equipped with AHC (in select global markets). Let’s begin with a theory. The 200-series LC (without AHC) and the LX570 (or LC with AHC) are like New York & LA. LC “purists” are like New Yorkers...Search results for query: AHC
Good Luck
The Lexus LX570 AHC/ACS systems are a significant evolution with many differences from the LX470/LC100 AHC/TEMS systems which first emerged 20+ years ago. There is great information on the fundamentals of the early system in this "100 series" forum but you need to see what the "200 series" forum has to offer to get into the detail of the next generation of these systems. Post #163 and onwards shows that @swiftie has read widely and maybe already has seen the attached two descriptive documents. If not, they may be of interest. In Australia -- and maybe some other parts of the world -- the LC200 cannot be had with AHC/AVS. These systems are available only on the Lexus LX570 (3UR-FE gasoline V8 5663 cc) and the more recent (since 2018) diesel variant (1VD-FTV diesel V8 4461 cc) designated here as the Lexus LX450d .....
Just flushed my 06LX at 223k. Previous flush was at 181k. Fluid was dark golden brown, like old brake fluid. Not nearly as bad as many here, but still old.
New fluid is light pink and the fluid at the end of my flush was a slightly pink-tinted gold. Definitely still plenty old fluid in the system. I'll do another round of flushing in a while when I have new bleeders and caps on hand. A couple of my bleeders were pretty rusty, but all broke loose easily and sealed well.
Thanks @PADDO for lining out the process and making it easy! My only hiccup was it took a few attempts to get the height control accumulator to fill. I kept opening the bleeder and very little fluid would come out. Then I went for a short drive and watched via Techstream. Once I saw the pressure build, I pulled into the garage again and bled. Boom, ~250ml.
New fluid is light pink and the fluid at the end of my flush was a slightly pink-tinted gold. Definitely still plenty old fluid in the system. I'll do another round of flushing in a while when I have new bleeders and caps on hand. A couple of my bleeders were pretty rusty, but all broke loose easily and sealed well.
Thanks @PADDO for lining out the process and making it easy! My only hiccup was it took a few attempts to get the height control accumulator to fill. I kept opening the bleeder and very little fluid would come out. Then I went for a short drive and watched via Techstream. Once I saw the pressure build, I pulled into the garage again and bled. Boom, ~250ml.
Thank you for those pdf's. I hadn't seen the general discussion pages on the AHC before and it filled in some gaps on my understanding so very grateful thank you. I hadn't realised that the front left right shocks were controlled by a valve during cornering but that was one of the main issues I had on the vehicle handling in that the front would dip into the corner quite severely and that combined with poor shocking response made for a very unpleasant driving experience on some road surfaces. Certainly changing the fluid has restored a lot of functionality to the suspension but I'm surprised about just how much improvement there has been. Someone who is knowledgeable on fluids and how they degrade could maybe explain why but looking at new versus old fluids visually there doesn't seem to be much to see apart from colour.
Hydraulic fluids and their characteristics and differences for different applications make up a deep field of study. Here are a few thought starters on different properties:
Selecting fluids for hydraulic pumps
As well as the fluid properties including age of the fluid, the properties of seals and valves also are important, as well as the operating conditions, especially high temperatures.
Mixing different kinds of fluids can lead to unintended consequences. For example, if brake fluid has entered the AHC system inadvertently or by simple mistake, then some breakdown of the diaphragm in the 'globes' and some O-rings can occur. In turn, fine particulate matter may cause blockages of tiny orifices in various parts of the system and/or build-up of sludge in the small filter 'socks' within the oil passages in the AHC pump.
New, correct AHC fluid is a pink-red colour -- anything else is due to fine particulates, oxidation of the fluid, or other fluids being present, including water.
Interesting read thanks, I was aware of some of that as I'm from an agricultural engineering background. The fluid was definitely contaminated after 95K miles but nobody had been near the system from new, not even the dealer (the access panel to the reservoir had never been opened) . I suspect it has picked up contamination internally from seals or other components. Oxidation through constant cycling of the fluid to and from the reservoir I think is also a factor which explains the darkening of the fluid maybe ? Lower viscosity is not helpful in a suspension system and maybe the primary cause of damping problems ?
(from your link)
(from your link)
It is getting a bit off topic but parts of the following well-illustrated thread may be of interest if not seen previously -- suggest start around Post #67. This relates to AHC pump issues and even though the LC100/LX470 AHC system is quite different to the LX570 AHC system, the AHC pump itself is similar. Some pictures of pump internals and the tiny internal filter 'socks' or 'strainers' are shown:
forum.ih8mud.com
AHC pump out? With code 1762
I have been, currently am and will continue to research this but wanted to post..... and can’t send @PADDO a pm. Brief to the point AHC issue... 2006 LX. Has been riding perfectly, (no bouncing like when globes are bad). I lowered truck for someone to enter then it would not raise back up to...
forum.ih8mud.com
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Sorry to revive this thread but this was the easiest and fastest method of flushing\bleeding the AHC I have stumbled upon.
Here's the old AHC fluid from my new to me 03 LX470. Feels like it was never replaced by PO. Bnew fluid from Toyota was light red.
Here's the old AHC fluid from my new to me 03 LX470. Feels like it was never replaced by PO. Bnew fluid from Toyota was light red.
Successfully flushed the system following this method. Took me about an hour.
Level and color on "low".
Empty reservoir.
The contents from reservoir. Just about 1.5 liters.
Color of old reservoir fluid.
Added approximately 2.5 liters of new fluid.
Level and color on "low".
Empty reservoir.
The contents from reservoir. Just about 1.5 liters.
Color of old reservoir fluid.
Added approximately 2.5 liters of new fluid.
Right after bleeding the accumulator and both driver side dampers.
Quantity of fluid that I was able to bleed. Just shy of 1 liter.
Condition of fluid that was bled.
Quantity of fluid that I was able to bleed. Just shy of 1 liter.
Condition of fluid that was bled.
Ok, I just attempted this yesterday and still working on it till this morning. Seems like my vehicle (2005 lx470 with 215000 miles) is stuck at L. When I start my vehicle I hear the pump kick on and it'll shut off after a minute and the OFF light will come on blinking. I tried to continue bleeding out the system thinking that there is air trapped somewhere but no luck. It seems like my accumulator is not filling at all. Do I need a new accumulator or is there something I'm missing?
Replied by accident...
