Disabling the AHC and AVS systems, no warning lights. (1 Viewer)

[turbo8]

There are aftermarket swaybars designed for non-kdss 200 series. Nolathane, Whiteline, Achtuning/Superpro. 30-39mm, depending on which ones you pick. Might be a good option if you remove AHC and find the stock swaybars lacking.

No front swaybar for me, hopefully I don't have to avoid a moose.

Hopefully my LX will do a little better than a stock Grand Cherokee.

 

[TeCKis300]

No front swaybar for me, hopefully I don't have to avoid a moose.

Hopefully my LX will do a little better than a stock Grand Cherokee.

Maybe counterintuitive, but from my track days tuning sway bars...

Having no front bar will actually increase front axle bite and increase the propensity for oversteer. Conversely, increasing front axle roll stiffness compared to the rear, will lead to more stable understeer.

Unfortunately, taking out the front sway bar wouldn't bode well for the moose test and potentially lead to more likelihood of oversteer into rollover, especially with a higher center of gravity.

 

[turbo8]

Maybe counterintuitive, but from my track days tuning sway bars...

Having no front bar will actually increase front axle bite and increase the propensity for oversteer. Conversely, increasing front axle roll stiffness compared to the rear, will lead to more stable understeer.

Unfortunately, taking out the front sway bar wouldn't bode well for the moose test and potentially lead to more likelihood of oversteer into rollover, especially with a higher center of gravity.

That is correct and have first hand knowledge. This happened to me in my 4runner a few years ago avoiding a couch in the highway going around 70mph.

I went from a quick right to avoid the couch to being sideways, counter steered left flipped me 180 degrees the other way instantly, facing the dividing wall. Counter steered a little less to the right and I was going straight again.

My 4runner at the time was really softly sprung, shocks needed a rebuild and my tires were under inflated.

Really greatful I didn't roll, wish I would have just crashed through the couch. 4runner has a 1/4 thick steel skid plate with a sub frame behind it...

My LX does do similar but nowhere near as much. Maybe around 25% as much.

 

[Heckraiser]

Yep, I rolled my 3rd gen 4runner in a similar oversteer maneuver. There was some ice/dry pavement involved though. They don't like going sideways on pavement

 

[B Hans]

Finally got a chance to install the new suspension (well, mostly). A couple notes based on my experience:

• Replaced the existing suspension with Fox 2.5" shocks, Total Chaos Upper Arms, and Icon progressive rear springs. The Fox coilovers don't require any modification of the spring tower like Turbo had to do for his Kings, though they interfere with the front height sensor bracket bolts so those had to be removed. I haven't been able to install the rear shocks yet. This wasn't very clear when I ordered everything, but apparently Fox requires you to re-use the existing upper bushings/retainer/washer stack from the OEM rear shocks. These are different on the LX than the Land Cruiser; the LX pieces are indexed because of the hydraulic lines so I had to order the OEM parts for a Land Cruiser from Toyota (hopefully they'll be here in a couple days so I can finish everything).
• Was able to remove all of the AHC components and lines intact, except for three lines: Two lines that go from the main AHC pump on the driver's rail over the gas tank crossmember to the passenger components, and the line from the passenger rear shock to the passenger frame rail, though I think I have a plan to get this one out when I finish up the rear. The long line from the rear reservoir to the main pump on the inside driver's frame rail can be disconnected into 3 pieces which makes it easier to remove.
• I was dreading removing the nuts on the top of the rear shocks based on what I read here (and experienced working on a friend's LC). These are especially annoying on the LX because the AHC connection bracket effectively hides most of the nut which makes it impossible to use a standard wrench like you can use on the LC. I ended up making a "tool" by welding a flat plate handle to a 22mm socket which was a game changer. I could flex the handle to move around things like the exhaust and gas tank as needed and made removal of these a non-issue. Since the AHC shock is indexed in the top mount you don't need to do anything to stop the shock from rotating like you have to do on the LC.

• Based on some of the comments in this thread, I spent some time trying to see if I could keep AFS working by disconnecting various parts of the AHC computer module and leaving certain fuses in place but wasn't able to get it to remain working. I'm guessing this is because I had to remove the front height sensors (I left the rears in place for this round of testing). I have HID's retrofitted in my headlights so losing AFS wasn't the end of the world.
• From what I can tell, if you leave the top plug in the module you will trigger the "Check AHC" code on the dash; leaving the second or third in place didn't seem to trigger anything so long as the top was disconnected. I ended up disconnecting all three plugs, pulling the two AHC fuses and AFS fuse in the passenger fuse panel, and the AHC relay from the engine fuse panel. I left the 60a AHC fuse in place. Like others, I get no dash lights or anything now.

• AHC fluid gets everywhere, despite my best efforts. I bled and drained every point I could think of and every time I disconnected something more fluid would drain from that location and elsewhere in a manner that seemed to defy physics and gravity, making a mess. Unless you have a catch pan the size of your vehicle, you're going to make a mess. Oh well.

I think the AHC removal was 80% of the work and time, the rest is pretty straightforward like any other vehicle. Hopefully I'll get the new shock parts this week so I can finish up the rear shocks and get this thing back on the road. I plan to install a Switch Pros panel in place of the AHC switches on the center console, hopefully making some sort of mount that blends into the existing area to make it as clean as possible. Need to finalize a design then figure out if I want to 3D print or fabricate something, but that's my initial plan for now.

- Brian

 

[tbisaacs]

Finally got a chance to install the new suspension (well, mostly). A couple notes based on my experience:

• Replaced the existing suspension with Fox 2.5" shocks, Total Chaos Upper Arms, and Icon progressive rear springs. The Fox coilovers don't require any modification of the spring tower like Turbo had to do for his Kings, though they interfere with the front height sensor bracket bolts so those had to be removed. I haven't been able to install the rear shocks yet. This wasn't very clear when I ordered everything, but apparently Fox requires you to re-use the existing upper bushings/retainer/washer stack from the OEM rear shocks. These are different on the LX than the Land Cruiser; the LX pieces are indexed because of the hydraulic lines so I had to order the OEM parts for a Land Cruiser from Toyota (hopefully they'll be here in a couple days so I can finish everything).
• Was able to remove all of the AHC components and lines intact, except for three lines: Two lines that go from the main AHC pump on the driver's rail over the gas tank crossmember to the passenger components, and the line from the passenger rear shock to the passenger frame rail, though I think I have a plan to get this one out when I finish up the rear. The long line from the rear reservoir to the main pump on the inside driver's frame rail can be disconnected into 3 pieces which makes it easier to remove.
• I was dreading removing the nuts on the top of the rear shocks based on what I read here (and experienced working on a friend's LC). These are especially annoying on the LX because the AHC connection bracket effectively hides most of the nut which makes it impossible to use a standard wrench like you can use on the LC. I ended up making a "tool" by welding a flat plate handle to a 22mm socket which was a game changer. I could flex the handle to move around things like the exhaust and gas tank as needed and made removal of these a non-issue. Since the AHC shock is indexed in the top mount you don't need to do anything to stop the shock from rotating like you have to do on the LC.

View attachment 3271557​

• Based on some of the comments in this thread, I spent some time trying to see if I could keep AFS working by disconnecting various parts of the AHC computer module and leaving certain fuses in place but wasn't able to get it to remain working. I'm guessing this is because I had to remove the front height sensors (I left the rears in place for this round of testing). I have HID's retrofitted in my headlights so losing AFS wasn't the end of the world.
• From what I can tell, if you leave the top plug in the module you will trigger the "Check AHC" code on the dash; leaving the second or third in place didn't seem to trigger anything so long as the top was disconnected. I ended up disconnecting all three plugs, pulling the two AHC fuses and AFS fuse in the passenger fuse panel, and the AHC relay from the engine fuse panel. I left the 60a AHC fuse in place. Like others, I get no dash lights or anything now.

View attachment 3271558​

• AHC fluid gets everywhere, despite my best efforts. I bled and drained every point I could think of and every time I disconnected something more fluid would drain from that location and elsewhere in a manner that seemed to defy physics and gravity, making a mess. Unless you have a catch pan the size of your vehicle, you're going to make a mess. Oh well.

I think the AHC removal was 80% of the work and time, the rest is pretty straightforward like any other vehicle. Hopefully I'll get the new shock parts this week so I can finish up the rear shocks and get this thing back on the road. I plan to install a Switch Pros panel in place of the AHC switches on the center console, hopefully making some sort of mount that blends into the existing area to make it as clean as possible. Need to finalize a design then figure out if I want to 3D print or fabricate something, but that's my initial plan for now.

- Brian

I always thought would be cool to reuse the dampening and height switches for something but it's not really possible. The switches themselves just push on rubber plungers on the circuit board below them.

 

[B Hans]

I always thought would be cool to reuse the dampening and height switches for something but it's not really possible. The switches themselves just push on rubber plungers on the circuit board below them.

Yeah, my thought is some sort of cover/mount that would go over the existing switches and flush mount the switch panel. The dimensions seem like they would work, but fitting something that would fit nicely mike take some work.

 

[AnyMal]

Finally got a chance to install the new suspension (well, mostly). A couple notes based on my experience:

• Replaced the existing suspension with Fox 2.5" shocks, Total Chaos Upper Arms, and Icon progressive rear springs. The Fox coilovers don't require any modification of the spring tower like Turbo had to do for his Kings, though they interfere with the front height sensor bracket bolts so those had to be removed. I haven't been able to install the rear shocks yet. This wasn't very clear when I ordered everything, but apparently Fox requires you to re-use the existing upper bushings/retainer/washer stack from the OEM rear shocks. These are different on the LX than the Land Cruiser; the LX pieces are indexed because of the hydraulic lines so I had to order the OEM parts for a Land Cruiser from Toyota (hopefully they'll be here in a couple days so I can finish everything).
• Was able to remove all of the AHC components and lines intact, except for three lines: Two lines that go from the main AHC pump on the driver's rail over the gas tank crossmember to the passenger components, and the line from the passenger rear shock to the passenger frame rail, though I think I have a plan to get this one out when I finish up the rear. The long line from the rear reservoir to the main pump on the inside driver's frame rail can be disconnected into 3 pieces which makes it easier to remove.
• I was dreading removing the nuts on the top of the rear shocks based on what I read here (and experienced working on a friend's LC). These are especially annoying on the LX because the AHC connection bracket effectively hides most of the nut which makes it impossible to use a standard wrench like you can use on the LC. I ended up making a "tool" by welding a flat plate handle to a 22mm socket which was a game changer. I could flex the handle to move around things like the exhaust and gas tank as needed and made removal of these a non-issue. Since the AHC shock is indexed in the top mount you don't need to do anything to stop the shock from rotating like you have to do on the LC.

View attachment 3271557​

• Based on some of the comments in this thread, I spent some time trying to see if I could keep AFS working by disconnecting various parts of the AHC computer module and leaving certain fuses in place but wasn't able to get it to remain working. I'm guessing this is because I had to remove the front height sensors (I left the rears in place for this round of testing). I have HID's retrofitted in my headlights so losing AFS wasn't the end of the world.
• From what I can tell, if you leave the top plug in the module you will trigger the "Check AHC" code on the dash; leaving the second or third in place didn't seem to trigger anything so long as the top was disconnected. I ended up disconnecting all three plugs, pulling the two AHC fuses and AFS fuse in the passenger fuse panel, and the AHC relay from the engine fuse panel. I left the 60a AHC fuse in place. Like others, I get no dash lights or anything now.

View attachment 3271558​

• AHC fluid gets everywhere, despite my best efforts. I bled and drained every point I could think of and every time I disconnected something more fluid would drain from that location and elsewhere in a manner that seemed to defy physics and gravity, making a mess. Unless you have a catch pan the size of your vehicle, you're going to make a mess. Oh well.

I think the AHC removal was 80% of the work and time, the rest is pretty straightforward like any other vehicle. Hopefully I'll get the new shock parts this week so I can finish up the rear shocks and get this thing back on the road. I plan to install a Switch Pros panel in place of the AHC switches on the center console, hopefully making some sort of mount that blends into the existing area to make it as clean as possible. Need to finalize a design then figure out if I want to 3D print or fabricate something, but that's my initial plan for now.

- Brian

If i ever rip AHC out, i will cut the sheet metal pinch weld above and around the shock tube nut in that location above the frame rail. Hard to get to is an understatement. Good work on that specialized tool, everyday i cant weld is a day im kicking myself.

Also, i dont have AFS, and im not sure what would be different, but my headlights do pivot up and down. I believe the auto level angle is based on ahc sensor, and i have no idea how that would ever not trigger some major fault if AHC master relay is fully pulled.

Do your lights operate as normal just dead straight? Not sure if your MY is manual angle adjustment or not. On my truck, it will do a little up down greeting when you turn it on with lights lit.

Yeah, not sure if id ever part with AHC at this point…

 

[tbisaacs]

Yeah, my thought is some sort of cover/mount that would go over the existing switches and flush mount the switch panel. The dimensions seem like they would work, but fitting something that would fit nicely mike take some work.

Oooh, here is another idea

Cut the end cap off, delete the two switches and the glue it all together. Where the switches are deleted you'd need just a flat peace of ABS or something to cover the hole and then you can surface mount or recess some switches.

 

[ThRiLlGmYr]

I hope to keep my AHC as long as possible, but it is great that you all have figured this all out. I have next to no mechanical skills and some parts of this thread lose me. If the day comes and I need to delete AHC, please tell me if I have this right?

1. Follow directions on pulling fuses
2. Remove stock shocks and springs
3. Install new shocks and springs (made for any particular model truck? LC, Sequoia, Tundra? Any recommended height? I don't care to go much over 33" tires".
4. Sway bar is probably important to me. Did I read correctly that there are aftermarket that work? Brand? Works with LX or do I need a Tundra front suspension?
5. Do any shops do these?

Thanks for any input.

 

[AnyMal]

I hope to keep my AHC as long as possible, but it is great that you all have figured this all out. I have next to no mechanical skills and some parts of this thread lose me. If the day comes and I need to delete AHC, please tell me if I have this right?

1. Follow directions on pulling fuses
2. Remove stock shocks and springs
3. Install new shocks and springs (made for any particular model truck? LC, Sequoia, Tundra? Any recommended height? I don't care to go much over 33" tires".
4. Sway bar is probably important to me. Did I read correctly that there are aftermarket that work? Brand? Works with LX or do I need a Tundra front suspension?
5. Do any shops do these?

Thanks for any input.

OEM non kdss sway and a few aftermarket ones out there too.

But yeah, you’ll need coil-overs up front and shocks / springs in the rear. Can be any brand but made for the 200. You can even do a full LC setup sans kdss.

 

[ThRiLlGmYr]

OEM non kdss sway and a few aftermarket ones out there too.

But yeah, you’ll need coil-overs up front and shocks / springs in the rear. Can be any brand but made for the 200. You can even do a full LC setup sans kdss.

Thanks for the clarification about coil overs. What determines your lift? The spring size? Do you think 2 inches is enough?

 

[AnyMal]

Thanks for the clarification about coil overs. What determines your lift? The spring size? Do you think 2 inches is enough?

Pretty much yes, and if I was in a static suspension id just go for at least 2”, probably 3” though . With you gutting an LX, you wont have that pesky KDSS link blocking your tire choices. So 2” on 34-35s is probably ideal without CoG being wildly raised above the pavement.

When you go aftermarket, the offerings that are extended travel would be the way to go. A stock LC setup would leav droop on the table lifted.

 

[grinchy]

Kdss is a cool system, shame no one has pioneered the retrofit for that.

 

[AnyMal]

Kdss is a cool system, shame no one has pioneered the retrofit for that.

@bloc has some kind of story on this subject.

 

[bloc]

@bloc has some kind of story on this subject.

Another awesome project from @bjowett

Not sure how far it got.

KDSS system

It took some searching, but a KDSS system was sourced and now delivered. It will live on my Tundra soon... for now all the parts sit. If anyone is interested in anything pertaining to the system, well, just ask and we can have a good look at it here...

forum.ih8mud.com

 

[bjowett]

That project truck was damaged and sold off. The KDSS parts are still in the barn.

 

[AnyMal]

@turbo8 Itssss showtime!

 

[turbo8]

@turbo8 Itssss showtime!

Ha, I don't think so!

 

[TeCKis300]

Ha, I don't think so!

Not saying to apply KDSS to new platforms, but I think the LC community can use some of that ingenuity you've brought to LXs.

They need a more aggressive and wholistic solution for a front relocation bracket. Probably something that brings the sway bar 1.25"-1.5" forward. Along with an A-Arm spacer bracket to better mount the end link to the outside LCA bucket. There's probably other unique ways to improve space constraints that haven't been explored yet. I would recommend a geometry that reduces KDSS motion ratio to increase flex, but still keep the anti-sway goodness.

There might also be a need for longer end links or to space the whole system down to better accommodate droop travel angles.

Maybe blasphemy, but KDSS delete! With new brackets to support standards sway bars.