Disabling the AHC and AVS systems, no warning lights. (3 Viewers)

[grinchy]

There is actually a box from Japan that may be able to address this issue. So box allows you to fine tune the ride height in a far more detailed manner than that AHC switch can. It can give you up to +70mm of lift and -40mm of lowering.

This is the control unit

Data System Air SUS Active Suspension Control Kit - ASR681II - RHDJapan - https://www.rhdjapan.com/data-system-air-sus-active-suspension-control-kit-asr681ii.html

This is the wiring

Data System Air SUS Active Suspension Control Kit Harness - LX570 URJ201W Land Cruiser URJ202W Kouki - RHDJapan

Data System Air SUS Active Suspension Control Kit Harness - LX570 URJ201W Land Cruiser URJ202W Kouki. Buy direct with global shipping to your door from Osaka, Japan. We speak English and all email queries are responded to promptly!

www.rhdjapan.com

The way it works is that it taps into the AHC sensor wires going to the AHC ECU via the adapter harness and modified the signal going in and out of it.

I have bought this one for my dad 2018 LX570 but didn't have the chance to install and test it.

Pretty neat. Sadly only work on 3rd gen LX . . .

 

[jbyrd78]

UPDATE:
I'm reporting back with a 2 week update of driving around on conventional 200 series Land Cruiser suspension in my 2015 LX570 since I told @paulunm I would.

As previously mentioned, my suspension setup is stock Land Cruiser springs & shocks.
In the past two weeks I have done alot of highway commuting to work(155 miles round trip), alot of driving around town, as well as some country road driving.
On the first drive and the first week of driving the LX after swapping the suspension,
I notice the ride comfort from the AHC was gone, but it was a decent ride until I could upgrade to something better considering the situation I got dealt.

During the 2nd week however, I think I found the game changer that really improved the ride, and made everything way better...the 15mm rear spacers in the picture provided. I know you guys are laughing and think I'm crazy, but seriously. I only installed these rear spacers b/c I noticed that the rear of my LX was sitting way to level with the front OEM spacers installed, and I wanted a bit of rake so the rear wouldn't look like it was sagging
First drive with the rear spacers installed, the whole family was in the LX and I instantly noticed a HUGE improvement in the ride quality. I didn't say anything when I noticed this b/c I wanted to see if anyone would speak up. On the third day, my girlfriend said " I don't know what those spacers you installed are supposed to do, but the LX feels so much better now that you installed them." She compared the ride to the middle comfort setting on the AHC suspension.
So if you decide to ditch your AHC system on your LX, and decided to use a conventional suspension kit, consider spending the extra hundred bucks and purchase a set of these poly spacers for the rear, because I'm being really serious when I say it was total game changer and improvement in the ride quality and comfort

 

[sedole]

Just did this mod. Like others I can confirm no warning lights and my AVS is still fully functional having left the height sensors and AVS fuse in position. I installed 6112/5160 Bilsteins in place of the AHC. I used the 177lb rate Bilstein rear springs and 15mm coil spacers to make sure I keep some rake. Can't say I would recommend this mod to everyone but I'm very happy.

Referencing everything to a max sensor lifted ride: side to side sway feels about as wallowy as driving in comfort mode and very slow speed bumps feel in between normal and sport in terms of harshness. But where the Bilsteins really shine are in their higher speed abilities. So much better control and composure and damping of bumps, especially considering I'm at a higher ride height now. Way outpaces the AHC. This was really my only complaint of AHC and my main reason for switching (aside from some failing AHC components which I could've replaced/rebuilt and the annoying drop at highway speeds). AHC high always felt really stiff and pogo-stick-like to the point of I'd really only ever turn it on to help get out of deep snow or to pose when parked lol. This is butter in comparison. For example, the parking lot where I took the side profile picture has an entrance that's about 8" higher than the lot. There are two turn ins with ramps and everything else is a 90 degree curb drop. I've hopped off the curb numerous times to go do donuts in the lot when it has snowed and boy is it a hard harsh hit with the AHC. I took it at about 25 mph with the Bilsteins and you literally cannot tell you just hopped of a curb. So smooth. Me likey.

Where the AHC really shines and what I truly will miss are just how damn flat it can corner. A 6,000+ lbs SUV should not be able to handle that good its ridiculous. And the auto adjusting for load. It's stupid good. I will miss it for the one time I tow per year. This in mind, I may consider a stiffer rear sway bar. In my limited driving so far I feel like the front is OK but the rear could use a little more help. I also may have inadvertently softened the effect of the rear sway bar by how much I lengthened my rear end links. Once I find something to drive up on and figure out how much clearance I have at full articulation I may shorten them a little. I'll probably also get some rubber spring coil booster spacers that I can swap out easily for long trips with heavy loads or towing.

For anyone considering Bilsteins with AHC, you won't find too much out there but I've read a total of two comments after scrolling multiple threads that the rear reservoirs might not have clearance with the rear sway bar. And I can confirm, they don't. You either have to delete the rear sway bar which I don't recommend, run the bar anyways and have it rub the bar which I don't recommend, or fab up extended end links which I do recommend. I extended my links by 2.5 inches. This may have been too much as it's more than my lift height but after taking measurements it's gotten me good clearance from the reservoir. At rest I've got about an inch of clearance. Barely flexed out on my 7" rhino ramps that clearance quickly drops to only about 1/2-3/8" clearance. I need to really get this thing flexed out and see if it rubs before I can make recommendations.

The shop that did my alignment claimed they couldn't get anymore than 2 degrees of caster. This might actually be true. I gave myself an eyeball alignment before taking it in as I did the install myself and I maxed caster all the way out then got camber as close to zero as possible. This is slightly less caster than I had with AHC sensor lifted and I felt that was a little light on center steering already. This is a little lighter still. Liveable for now but I will be looking into aftermarket UCAs this summer.

Aaand that brings us to ride height. Center of hub to edge of fender before and afters, all measurements taken with a half tank of gas:
Driver Front: 20 5/8" to 21 1/2"
Passenger Front: 20 7/8" to 21 3/4"
Driver Rear: 20 3/4" to 22 1/4"
Passenger Rear: 21 3/8" to 23"

I don't have measurements from before the sensor lift but I do remember it lifting me about 1 1/4" all around. That puts stock measurements around the 19 1/2" range. As you'll notice I've got a lot of driver lean. I am going to try playing with different spacer thicknesses once I go back in and remove all the AHC components. I've heard altogether they weigh in the 200-300 lbs range.

Anyways enough rambling, here's some pictures:

 

[jbyrd78]

Just did this mod. Like others I can confirm no warning lights and my AVS is still fully functional having left the height sensors and AVS fuse in position. I installed 6112/5160 Bilsteins in place of the AHC. I used the 177lb rate Bilstein rear springs and 15mm coil spacers to make sure I keep some rake. Can't say I would recommend this mod to everyone but I'm very happy.

Referencing everything to a max sensor lifted ride: side to side sway feels about as wallowy as driving in comfort mode and very slow speed bumps feel in between normal and sport in terms of harshness. But where the Bilsteins really shine are in their higher speed abilities. So much better control and composure and damping of bumps, especially considering I'm at a higher ride height now. Way outpaces the AHC. This was really my only complaint of AHC and my main reason for switching (aside from some failing AHC components which I could've replaced/rebuilt and the annoying drop at highway speeds). AHC high always felt really stiff and pogo-stick-like to the point of I'd really only ever turn it on to help get out of deep snow or to pose when parked lol. This is butter in comparison. For example, the parking lot where I took the side profile picture has an entrance that's about 8" higher than the lot. There are two turn ins with ramps and everything else is a 90 degree curb drop. I've hopped off the curb numerous times to go do donuts in the lot when it has snowed and boy is it a hard harsh hit with the AHC. I took it at about 25 mph with the Bilsteins and you literally cannot tell you just hopped of a curb. So smooth. Me likey.

Where the AHC really shines and what I truly will miss are just how damn flat it can corner. A 6,000+ lbs SUV should not be able to handle that good its ridiculous. And the auto adjusting for load. It's stupid good. I will miss it for the one time I tow per year. This in mind, I may consider a stiffer rear sway bar. In my limited driving so far I feel like the front is OK but the rear could use a little more help. I'll probably also get some rubber spring coil booster spacers that I can swap out easily for long trips with heavy loads or towing.

For anyone considering Bilsteins with AHC, you won't find too much out there but I've read a total of two comments after scrolling multiple threads that the rear reservoirs might not have clearance with the rear sway bar. And I can confirm, they don't. You either have to delete the rear sway bar which I don't recommend, run the bar anyways and have it rub the bar which I don't recommend, or fab up extended end links which I do recommend. I extended my links by 2.5 inches. This may have been too much as it's more than my lift height but after taking measurements it's gotten me good clearance from the reservoir. At rest I've got about an inch of clearance. Barely flexed out on my 7" rhino ramps that clearance quickly drops to only about 1/2-3/8" clearance. I need to really get this thing flexed out and see if it rubs before I can make recommendations.

The shop that did my alignment claimed they couldn't get anymore than 2 degrees of caster. This might actually be true. I gave myself an eyeball alignment before taking it in as I did the install myself and I maxed caster all the way out then got camber as close to zero as possible. This is slightly less caster than I had with AHC sensor lifted and I felt that was a little light on center steering already. This is a little lighter still. Liveable for now but I will be looking into aftermarket UCAs this summer.

Aaand that brings us to ride height. Center of hub to edge of fender before and afters, all measurements taken with a half tank of gas:
Driver Front: 20 5/8" to 21 1/2"
Passenger Front: 20 7/8" to 21 3/4"
Driver Rear: 20 3/4" to 22 1/4"
Passenger Rear: 21 3/8" to 23"

I don't have measurements from before the sensor lift but I do remember it lifting me about 1 1/4" all around. That puts stock measurements around the 19 1/2" range. As you'll notice I've got a lot of driver lean. I am going to try playing with different spacer thicknesses once I go back in and remove all the AHC components. I've heard altogether they weigh in the 200-300 lbs range.

Anyways enough rambling, here's some pictures:

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Welcome to the club. I installed stock Land Cruiser suspension on my LX570 w/ OEM front spacers. Going this route made the rear look lower than the front, and I also had driver side lean. I started experimenting with spacers, and ended up with a 30mm spacer on the rear driver side, and a 15mm spacer on the passenger side rear to level the rear out.

 

[sedole]

Welcome to the club. I installed stock Land Cruiser suspension on my LX570 w/ OEM front spacers. Going this route made the rear look lower than the front, and I also had driver side lean. I started experimenting with spacers, and ended up with a 30mm spacer on the rear driver side, and a 15mm spacer on the passenger side rear.

Fun club to be in!

That's a good point of reference, thank you. I will try removing the spacer on the passenger only since I've already got 15mm spacers and see how that looks.

 

[JohnnyLX570]

I have deleted the whole AHC, AVS, and AFS(disabled) systems and been driving around since January 2020 without problems.
View attachment 2884213
View attachment 2884212

Today I attempted the first steps into getting rid of the AHC/AVS systems, I think I was successful. I still need to do some more testing to make sure warning lights don't come on, like taking out the shocks.

Here is what I did:
Put vehicle in low mode(didn't know what was going to happen, so I figured this was the safest setting to be in)
Disconnect the battery
Pulled the AHC relay in the engine compartment fuse box.
Pulled 2 ACH fuses and 1 AFS fuse from the passenger side fuse box.
Disconnected the AHC ecu in the back of the vehicle.
Waited 30 min.
Reconnected the battery.

The little lcd screen no longer shows the vehicle height position and no warning lights. The AHC/AVS levers and the off button don't do anything nor do the lights come on when toggled.

I drove it around the block up to 25mph without any warning lights. I was checking to see if it would try to raise itself up and throw an error.

I then disconnected the battery and put everything back together. All systems functioned as normal.

If @Wotan or @bacalis would like to try this and verify it works that would be great.

View attachment 2094830

Do this at your own risk, you may mess up your vehicle.
AFS is different on 2016+ models this still needs a work around.

How has it worked out? Do you have a higher lift without the AHC. I did a sensor lift on my 2013 so I am always a couple inches higher (L N H), no warning lights etc. Added a 12,000 winch behind the stock grill. Look for me I'm always out on a back road in Las Vegas, Utah, or AZ.

 

[TeCKis300]

Referencing everything to a max sensor lifted ride: side to side sway feels about as wallowy as driving in comfort mode and very slow speed bumps feel in between normal and sport in terms of harshness. But where the Bilsteins really shine are in their higher speed abilities. So much better control and composure and damping of bumps, especially considering I'm at a higher ride height now. Way outpaces the AHC. This was really my only complaint of AHC and my main reason for switching (aside from some failing AHC components which I could've replaced/rebuilt and the annoying drop at highway speeds). AHC high always felt really stiff and pogo-stick-like to the point of I'd really only ever turn it on to help get out of deep snow or to pose when parked lol. This is butter in comparison. For example, the parking lot where I took the side profile picture has an entrance that's about 8" higher than the lot. There are two turn ins with ramps and everything else is a 90 degree curb drop. I've hopped off the curb numerous times to go do donuts in the lot when it has snowed and boy is it a hard harsh hit with the AHC. I took it at about 25 mph with the Bilsteins and you literally cannot tell you just hopped of a curb. So smooth. Me likey.

View attachment 3591481
View attachment 3591482

Great input and I enjoyed reading your journey in tuning your rig. Great to see another member in there cutting and fabricating parts.

Just a caveat to your impressions between AHC high stiffness and Bilstein's, there may be something else at play. One of the wear modes of AHC is the accumulators losing nitrogen pressure, just like gas charged shocks. The result of that is lost volume before the accumulator membrane bottoms out. This manifests in less compliance travel, particularly in AHC high where more of the load is transferred from the coil springs to the accumulator. A harsh ride in high, or lost compression compliance, is the direct symptom of worn accumulators - and perhaps the root of your comparison. Same symptom can show up when loading the car with high payloads.

Not to take away from Bilstein's as I do also own their products in my other cars. In a well maintained and working AHC system, AHC high is just as compliant and slinky as in normal position. I can assure you that the system is well up to task of hard and fast running over the roughest terrain.

 

[sedole]

Great input and I enjoyed reading your journey in tuning your rig. Great to see another member in there cutting and fabricating parts.

Just a caveat to your impressions between AHC high stiffness and Bilstein's, there may be something else at play. One of the wear modes of AHC is the accumulators losing nitrogen pressure, just like gas charged shocks. The result of that is lost volume before the accumulator membrane bottoms out. This manifests in less compliance travel, particularly in AHC high where more of the load is transferred from the coil springs to the accumulator. A harsh ride in high, or lost compression compliance, is the direct symptom of worn accumulators - and perhaps the root of your comparison. Same symptom can show up when loading the car with high payloads.

Not to take away from Bilstein's as I do also own their products in my other cars. In a well maintained and working AHC system, AHC high is just as compliant and slinky as in normal position. I can assure you that the system is well up to task of hard and fast running over the roughest terrain.

Oh no I definitely agree with you. I should have been more specific. My globes were definitely on their way out which is a good point I should have brought up. And absolutely something anyone reading this later should bear in mind.

Compared to 35,000 miles ago the AHC handled much better all across the board and I wouldn't have called that harsh over big bumps but one thing I remember noticing back then was almost a sensation like the suspension (mostly in front) would bottom out say for example when running through an intersection with a draining dip or speed bump at like 15-30 mph in comfort or normal mode and in normal height. If I bumped to sport or to high mode (in either normal or sport) or just slowed down--but that's no fun lol--it wouldn't have that bottoming out sensation, nor would I call it harsh and pogo-like. But it wasn't exactly 100% smooth either. I'm having trouble trying to describe it. I'd still say the Bilsteins are a little smoother than that. But that was also a lot of miles ago and I won't sit here and pretend I've got the absolute most perfect memory of it.

But yeah I agree that AHC is definitely up to the hard and fast running task. That's why I kept it for 35k+ miles even though I went into buying the truck thinking I'd yank it right away. I was very pleasantly surprised. Sure it had a couple small things that kept me wishing but I have a sometimes stupid internal drive to modify things when they're really already suited to the task--but it was great enough to keep me satisfied for a good while until it went bad.

 

[turbo8]

How has it worked out? Do you have a higher lift without the AHC. I did a sensor lift on my 2013 so I am always a couple inches higher (L N H), no warning lights etc. Added a 12,000 winch behind the stock grill. Look for me I'm always out on a back road in Las Vegas, Utah, or AZ.

It has worked out great. I'm sitting about 6" higher than stock. 4-5" increased from ride height and 1-2" from 35" tires. I also still have 3-4" of suspension droop.

 

[sedole]

Nolathane 30mm rear sway bar installed tonight. Visually a bit more beefy than stock for sure. Quick drive around the block shows a noticeable reduction in body roll. Will report back how it feels when I drive up and down the mountains this weekend.

Buuuut...back to square one with the end links. They contact the reservoirs within 6.5" of down travel. Will have to extend them a little more. Clearance picture taken on level ground.

Should be wayyy faster too now. Red gives +15 buff horses, right?

Edit: big difference. Stock swaybars with extended links felt a touch more wallowy/body rolly than AHC in comfort mode. This immediately brought it to around the same as normal mode AHC. Feels a lot more balanced as well. The truck felt more understeery with the stock bar.

However after extending the links from 5.25" to 7.25" (factory is 2.75") I'd now say it's in between comfort and normal AHC. I think I've got clearance to spare so once I get this thing flexed out and take more measurements I can see about shortening the links and tightening up the rear end again.