Undo AHC Delete / Restoration of AHC Help!! (1 Viewer)

[neo2uzfe]

Dear Fellow 100 series lovers,
I own a 05 LX470 which is at 280k kilometers. When I got it, the previous owner already had the AHC deleted. It was on conventional LC Shocks with AHC springs. Recently I replaced all shocks and springs with OEM LC100 new shocks and springs(used). Still on AHC Torsion bar (Still I wonder how it is not sagging at front end). After going through a Ton of AHC delete/ not posts here I'm still searching for a AHC undo delete post. I really like the smooth ride of AHC and would like to restore the AHC system. Despite replacing to new LC shocks and spring, I still feel every crack/ stones/ interlocks into the cabin. I'm not sure Non-AHC Torsion bars would help. I even replaced front and rear sway bar bushings, cushions etc. Still I don't feel the ride comfort is par with a Lexus. I don't know what is the present condition of the existing AHC components in the truck such as accumulators/pumps/lines etc. I will attach some photos. If anyone has attempted any AHC resurrection like this, please guide me the components and $$$ to be used. I would welcome any related guides/ posts/ links. I would also welcome the alternative comments. I do a minor amount of Beach/ Sand Off-roading but not looking for LIFT/ attachments etc. Cheers to all LX470/100 dudes out here.

 

[neo2uzfe]

Bump!! Anyone.

 

[awesomeissquid]

Have any pictures of the engine bay where the AHC pump and reservoir should be?

 

[neo2uzfe]

Have any pictures of the engine bay where the AHC pump and reservoir should be?

Matter of fact, yeah. There is something like the remains of ahc reservoir and pump. Please Excuse the diy lid

 

[NE Snowman]

Looks like you got parts still hooked up, the real question is why did the last owner drop it. Globes/lines/sensors or just wasn’t sure and had it deleted.

You should dig through the ABCs of AHC and see what’s in that thread. A TON of information there. The rear shock top nut I believe is going to be one of the harder places to reach.

 

[neo2uzfe]

Looks like you got parts still hooked up, the real question is why did the last owner drop it. Globes/lines/sensors or just wasn’t sure and had it deleted.

You should dig through the ABCs of AHC and see what’s in that thread. A TON of information there. The rear shock top nut I believe is going to be one of the harder places to reach.

Sure. Will do that. I already have gone through that thread a few times. Looks to be baselining and tuning/fixing of already working ahc whereas this one looks dead. Reason for Previous delete is still a mystery. It was having 9.00-16 bias ply tires when I got it. May be it was for a free(tire) lift or might have caused problems and he didn’t want to retain.

 

[suprarx7nut]

If you have all the lines attached and not cut, you might just need new shocks and globes.

Check the lines that run up to the top of each shock and see if they are present and undamaged.

Expect to pay for new shocks and globes at a minimum. Should be under $2k USD.

 

[neo2uzfe]

If you have all the lines attached and not cut, you might just need new shocks and globes.

Check the lines that run up to the top of each shock and see if they are present and undamaged.

Expect to pay for new shocks and globes at a minimum. Should be under $2k USD.

Hopefully that will be the extend of it. I haven’t checked the top part of the shocks. It has been replaced recently, may be multiple times including the previous ownership. Anyway Im gonna crawl under the truck tomorrow to check if there’s any hydraulic line above the shocks. Just incase there isn’t one, is it possible to repair/fix the lines? Or to be replaced as a whole. Looks like I have to forage for parts in Scrap yards.

 

[suprarx7nut]

Hopefully that will be the extend of it. I haven’t checked the top part of the shocks. It has been replaced recently, may be multiple times including the previous ownership. Anyway Im gonna crawl under the truck tomorrow to check if there’s any hydraulic line above the shocks. Just incase there isn’t one, is it possible to repair/fix the lines? Or to be replaced as a whole. Looks like I have to forage for parts in Scrap yards.

It's possible to replace the lines, just time consuming/difficult. When they were manufactured in the plant, I believe all the AHC lines were laid in place before the body went on the frame.

 

[neo2uzfe]

It's possible to replace the lines, just time consuming/difficult. When they were manufactured in the plant, I believe all the AHC lines were laid in place before the body went on the frame.

Yes. And I guess, no garage would want to waste their time and effort for it. Thanks YotaMD. Btw, your “why you should keep AHC” video is one of the inspiration behind this new quest of mine. Thank you.

 

[neo2uzfe]

This is one of the earlier obd scan reports. Don’t know whether this came after they disconnected ahc relay or fuses etc Or the sensor had actually failed.

 

[suprarx7nut]

Yes. And I guess, no garage would want to waste their time and effort for it. Thanks YotaMD. Btw, your “why you should keep AHC” video is one of the inspiration behind this new quest of mine. Thank you.

Glad to hear the video helped you! To be clear though - reviving a deleted system can be way harder than just doing the simple upkeep on a functional system. AHC is relatively easy to keep running, but all bets are off if it's been removed/left open to elements.

View attachment 3343748
This is one of the earlier obd scan reports. Don’t know whether this came after they disconnected ahc relay or fuses etc Or the sensor had actually failed.

Without verifying wiring and power to the ECU, the codes here aren't worth much.

 

[jsloden]

You won't need new shocks unless those are leaking. Even then, they only usually only leak if the pressures are too high. The globes on the other hand will more than likely need to be replaced. The cheapest place to get them are from ipex japan. I believe they are around $500 for the set from there. There are a few people on here that have ordered from them and they are legit. If any of the lines are rusted though I would honestly just leave it deleted. Rust is not something you want to tackle with this system.

 

[neo2uzfe]

If you have all the lines attached and not cut, you might just need new shocks and globes.

Check the lines that run up to the top of each shock and see if they are present and undamaged.

Expect to pay for new shocks and globes at a minimum. Should be under $2k USD.

Photos warning!!

Went underneath the truck today for check the condition of the hydraulic lines. There are Flexible hoses tucked with cable tie nearby top shock mounts on all four Shocks. And there are some wiring looking like sensors. underbody there are many metallic lines looking like hydraulic, the lines connected to accumulators look surface corroded from outside. I'm no means expert in determining the components health by looking at it. I will post the photos I took.

Looks like they have bent the lines and covered it with something like cloth and tape.

Many more photos are there, which I managed to capture by crawling in awkward postures ( No Hoist) but can attach only 5.

Some Flexible lines are broken, but looks like $60 replacement.

What does it look like? A $3K Experiment or LC100 Torsion bars?? . As I briefly gone through some Online FSM, it looks like a number of systems should work in tandem in good condition like steering,sensors, ahc components, abs wheel speed semsors etc etc ,Which may or may not require additional attention.

 

[neo2uzfe]

I haven’t ditched this far to accomplish goal of mine. Hence trying to gather more info. I have gone through countless AHC threads on the forum. And daily checking here and there in my lx. And similar to a thread I saw, I have no AHC dashlights. Neither H,N,L nor OFF. checked cowl panel fuses 20A, 15A are there. Checked Relay on the AHC ECU( clicking when given 12v). Checked other relays and fuses on engine bay. Checked connections to AHC ecu. Everything is there connected. But don’t know where to start power circuit testing. An ebay vci cable is awaiting delivery. But I suspect that be of any use if ECU is not getting power. On the height control switch only up and down are illuminated. How to test electrically everything is fine? In other words, could it be fried ECU? I really want to resurrect this dead AHC. once I make sure electricals are ok, I can source other components and try installing them. I’m putting my hope on AHC guru’s of the forum. Any video of diagnosing a dead AHC will be of great help. Where to check for alternator input to ahc?

 

[neo2uzfe]

I forgot to add that I have gone through lc100.github manual a fair bit of time as well. But the diagnosis steps seem a bit complex. I gone to a technician. He suggests me to continue with lc springs and bars. Such an ahc hater!! I suppose he doesn’t want to spent that much time. @suprarx7nut

 

[Bisho]

Not trying to detour you off your quest, but I see you are running ATs, can’t tell but I’m guessing load range E? Those 10 ply tires are going to give you a rougher ride, especially if you are running the pressures high. I experimented quite a bit and settled on 33psi for mine. Much better ride than 40 psi and no change in wear or mpg.

 

[neo2uzfe]

Not trying to detour you off your quest, but I see you are running ATs, can’t tell but I’m guessing load range E? Those 10 ply tires are going to give you a rougher ride, especially if you are running the pressures high. I experimented quite a bit and settled on 33psi for mine. Much better ride than 40 psi and no change in wear or mpg.

Yes bro, Those are A/T’s. But not E rated. They are P265’s. Anyhow, the ride is harsh. Pressures are somewhere around 35. It is annoying when you ride on not so smooth roads,interlock roads, small speed bumps and speed gradations on the ramps etc especially at low speeds. The whole vehicle rattles. Don’t even think about corrugations. More annoying fact that you go through all these vibrations and rattling on a landcruiser( technically lexus without ahc). Checked the bushes, all are fine. I don’t know AHC will make a difference in those conditions as my body mounts could be very old. Thanks for the tire suggestion though.Lately, I’ve been thinking about michelins too.

 

[Wilsil]

Another component to check for you are the levelling sensors, 2 in the front (left and right) and 1 in the rear.
Are they still there and attached mecanically and electronically?

 

[neo2uzfe]

Another component to check for you are the levelling sensors, 2 in the front (left and right) and 1 in the rear.
Are they still there and attached mecanically and electronically?

Not attached mechanically. The linkages are not there. Only the sensor part and wiring. But that is one of many things which is to be replaced. My current quest is whether the system is completely dead or not. As I don’t have dashlights despite fuses, relays, ecu are connected(visibly, not checked for function). Will techstream reveal what electronic parts are having trouble even if ecu is dead?