LX570 AHC “Basics” - Added as sticky thread for AHC Issues (5 Viewers)

[FinallyGotOne!]

I failed to copy and save the LX-570 procedure from the TSM the last time I paid for a 2-day subscription. Dang it. Here's an LX-470 procedure, which should be about the same for the LX-570:

Props to PADDO's AHC fluid replacement method!

 

[longranger]

Thank you very much. The filler is the white twist cap with the hose in it right? I'm going to need a longer suction hose for sure.

Not 100% sure. I had the local dealer perform the fluid change bc I’m working on getting good “baseline” values prior to adding extra weight, and needed it to be as close to factory as possible — and the mechanic who did the fluid flush knows this truck in and out. The dealer service cost for this was very high — $330 — but for folks getting used LXs, getting the suspension AHC green light from mechanics certified in this system is well worth it. Also, if anything should be perceptibly off, it’s relatively easy to get corrective work.

NOTE: make sure you speak to the mechanics who will be doing the fluid flush to gauge their level of knowledge of the system. The mechanic who is helping me started by pointing out that one of the biggest ways folks screw up their AHC is by putting in “wrong fluid like brake fluid or something” — for me, that was the magic opening phrase I needed to hear bc that’s been a common cause for concern on this forum (mechanics free styling and messing up AHC by filling with wrong fluid). A number of AHC questions and answers later, and I felt very comfortable turning the truck over to them.

Going to pick up the truck shortly and hopefully will return back with “before” and “after” fluid samples.

 

[Mixelplix]

I'm interested to see if the fluid comes back dark like it often is in the 100 series.

 

[txtortoise]

1. This is an awesome thread and would someone link to it in the FAQ.

2. I wish PADDO in the 100 forum would buy a LX 570, though I expect he’d have less to deal with in this current AHC generation.

 

[longranger]

I'm interested to see if the fluid comes back dark like it often is in the 100 series.

Here are the “before” and “after” photos of the fluid, with the annotations giving add’l context. This was the first fluid flush for this truck since the factory. AHC system was working well prior to flush, so the flush wasn’t mechanically necessary per se but it was overdue according to the maintenance schedule. So decided to get this done to get a “factory”-like baseline prior to adding more weight to the rear, and so on.

First impressions on the drive back from the flush — the suspension dampening feels noticeably better. I drove back on the recommended middle dampening setting, on bad city roads and good & very bad freeway surfaces. The LX felt very sure-footed before, but it feels just a little bit more balanced. Not a radical difference, but a noticeable difference.

Next thing I noticed is that the viscosity of the old fluid and new fluid is the same. It runs like apple juice or grape juice, a little bit “stickier” than water, but flows just as easily. This was my big concern going in, wondering whether, as the fluid “ages”, if there is any evaporation or thickening, which can lead to blockage in the smaller fluid passages in the overall AHC setup (same logic as blood thickening as risk factor for heart attack or stroke). To my great relief, no such finding here. Same viscosity in the fluids, which suggests the “old” fluid could have kept on raising and lowering for significantly longer.

 

[TonyP]

longranger is officially the Andy Kaufman of Mud.

 

[gaijin]

His "sensory analysis" capabilities rival the best dedicated analytical labs. Imagine, being able to accurately measure viscosity by looking at the liquids. Truly unbelievable

 

[longranger]

1. This is an awesome thread and would someone link to it in the FAQ.

2. I wish PADDO in the 100 forum would buy a LX 570, though I expect he’d have less to deal with in this current AHC generation.

Thank you for the kind words abt the thread. I’m convinced that with enough time, this forum thread will get us to a point where we’ll be able to essentially reverse-engineer the way the 200-series AHC works, including its electronics — which will potentially unlock a ton of additional functionality (overriding speed auto-limiting — drops from H to N above 30mph; from L to N automatically above a given speed limit, etc.). There is a lot of work to be done before we get there, as this is a complex system, but I’m sure it’s only a matter of time before we have even more manual override capability.

There are certain basics that we should gather data points on:

What is the chemical composition of the Toyota AHC fluid? I haven’t found this info anywhere, and it seems key for analyzing the “actual” limits of the AHC, as opposed to theoretical limits. This is especially true concerning temperature curves; meaning, can the system go far beyond minus 30 Celsius?

What’s the actual freezing point for this fluid? We’re told the system won’t work below 30 Celsius. But what’s the actual freezing temp for the fluid. This is a big deal, of course, because frozen fluid starts to pose serious structural threats, not only to easily-moddable things like plastic inlets and reservoir tanks, but also to the shocks. The easiest way to get this info would be to track down Alaskan/Siberian/Canadian/Patagonian LXers, or some university physics students with access to a cryo lab. I’m sure we’ll get the answer soon, but til then, the -30 Celsius floor seems very constraining. It’s like being told you have a “go-anywhere” machine, but whatever you do, “don’t go to Toronto or Manitoba in February.” We’ve already heard reassuring words from at least one Alaskan on this thread (Go Last Frontier!) and we all know the specs are conservative, but I think it behooves folks with AHC to really test the outermost limits of the system, so that the AHC community has more solid data to drive on.

Other AHC questions?

 

[longranger]

His "sensory analysis" capabilities rival the best dedicated analytical labs. Imagine, being able to accurately measure viscosity by looking at the liquids. Truly unbelievable

Don’t be haters. “Smell tests,” “knock tests,” “sway tests” — which seem subjective and voodoo to most outside observers — are at the heart of automotive diagnostic work.

Next time you see a long range truck driver beating trailer tires with a baseball bat, you should maybe take a listen. Andy Kaufman would.

What do your “best dedicated analytical labs” tell you about the freezing point and chemical formula of this Toyota AHC fluid? If the answer is crickets, get off this thread, shake off your giggles, and help us find the answer.

Until then, this is the first side-by-side before and after photo of AHC fluid that I’ve seen anywhere, especially with mileage & service history annotations. I’m asking knowledgeable and well-trained LX mechanics what the fluid is and scraping bits of knowledge from different sources and trying to aggregate it for folks who may find it useful.

If you don’t find this useful, then stop reading and go find a slice of mud where you’ll be more at home. But stop the cuckling ‘cause it’s getting annoying as ffaaaaaaa.

 

[longranger]

I’m in Alaska, as for the extreme cold. I have a 2013 LX and the last 4 or 5 winters have been mild (by our standards). The coldest I remember was -28 in my way to work and that was this past January. I remembered the -30 thing so I lowered it and raised it back up with no warning lights or drama.

Thank you for sharing this — the northernmost I’ve been in Alaska was 100 miles north of the Yukon River or thereabouts, in a late 90s Tacoma that was laughing at the washboard roads at 60mph speeds. My dream is to return in the LX, and get as far as the North Slope/Arctic.

In summer, AK temps can get cold but generally within LX temp-curves, so no worries temp-wise. But of all the roads I know, the Dalton Highway (Fairbanks to Arctic) around February would be the best for testing the true limits of the LX suspension — across a broad speed curve. If you know LXers who’ve done it, pls share.

 

[longranger]

Another key 200-series AHC question: what’s the spec volume of AHC fluid that’s supposed to be circulating in the system at any given time (not just reservoir, but across the whole system)?

In the 100-series it was about 5 liters (based on flush volumes that folks recorded) — is that correct? Here’s a 2010 post by @ntsaint where I’m getting this from (text boxes are mine/screenshot is of original).

 

[longranger]

Here’s another carry-over post from 100-series AHC, and hoping @PADDO can offer guidance as well on AHC performance and suggested maintenance.

 

[coleAK]

Thank you for sharing this — the northernmost I’ve been in Alaska was 100 miles north of the Yukon River or thereabouts, in a late 90s Tacoma that was laughing at the washboard roads at 60mph speeds. My dream is to return in the LX, and get as far as the North Slope/Arctic.

In summer, AK temps can get cold but generally within LX temp-curves, so no worries temp-wise. But of all the roads I know, the Dalton Highway (Fairbanks to Arctic) around February would be the best for testing the true limits of the LX suspension — across a broad speed curve. If you know LXers who’ve done it, pls share.

Of all the people up here I know with 200 series LX or LC. I’m the only one that drives it at all off road. I know a few guys with LX 470s I’ll ask if they have been colder. I’ve been in -47 just north of Anchorage in my 10 years up here but that was befor I had my LX.

 

[SWUtah]

Thank you for the kind words abt the thread. I’m convinced that with enough time, this forum thread will get us to a point where we’ll be able to essentially reverse-engineer the way the 200-series AHC works, including its electronics — which will potentially unlock a ton of additional functionality (overriding speed auto-limiting — drops from H to N above 30mph; from L to N automatically above a given speed limit, etc.). There is a lot of work to be done before we get there, as this is a complex system, but I’m sure it’s only a matter of time before we have even more manual override capability.

There are certain basics that we should gather data points on:

What is the chemical composition of the Toyota AHC fluid? I haven’t found this info anywhere, and it seems key for analyzing the “actual” limits of the AHC, as opposed to theoretical limits. This is especially true concerning temperature curves; meaning, can the system go far beyond minus 30 Celsius?

What’s the actual freezing point for this fluid? We’re told the system won’t work below 30 Celsius. But what’s the actual freezing temp for the fluid. This is a big deal, of course, because frozen fluid starts to pose serious structural threats, not only to easily-moddable things like plastic inlets and reservoir tanks, but also to the shocks. The easiest way to get this info would be to track down Alaskan/Siberian/Canadian/Patagonian LXers, or some university physics students with access to a cryo lab. I’m sure we’ll get the answer soon, but til then, the -30 Celsius floor seems very constraining. It’s like being told you have a “go-anywhere” machine, but whatever you do, “don’t go to Toronto or Manitoba in February.” We’ve already heard reassuring words from at least one Alaskan on this thread (Go Last Frontier!) and we all know the specs are conservative, but I think it behooves folks with AHC to really test the outermost limits of the system, so that the AHC community has more solid data to drive on.

Other AHC questions?

Looks like 60k mile service will be great for a Mall cruiser that’s spent its life in northern Florida and South Georgia.

 

[longranger]

Here’s a slightly different 200-series AHC fluid flush technique, courtesy of @jenlain from a different thread.

 

[longranger]

FWIW — another performance benchmark following the dealer “AHC fluid flush” — the “kneeling” function (suspension dropping to Low when parking) now works in 3 seconds as opposed to 5, and seems smoother.

 

[TonyP]

A lot can happen in two seconds...

 

[coleAK]

I talked to a guy I know with a LX470. He had been in -40 to -60 with his regularly as he has a cabin near Denali and spent 5 years in Fairbanks. He said had never gotten an error or failure just the one time he tested it at -60 it wouldn’t lower or raise although he also mentioned he did the test within 5min of starting it to make sure it was as cold as possible.

 

[longranger]

A lot can happen in two seconds...

Maybe, but shaving two seconds out of about five is a 40% improvement, so that’s significant. Also, Toyota documentation (can’t remember if it was manual or some suspension-specific publication) said that at most, the lift from N to H should take about 15 seconds at most. Just wanted to share this info in case it may be useful.

@coleAK — you are awesome for tracking this info down. Thank you! Logic suggests the 200-series AHC would perform even better than the 100-series — so this is very useful. Lastly, the -40 & -60 are of course Celsius — but feel it necessary to clarify in case others see that post without the earlier thread context.

 

[coleAK]

Sorry. No that’s Fahrenheit. So would be like -40 to -50 Celsius.