Slew of AHC codes

[wabiwasabi]

Hello! New here and going against a lot of the advisable research I did, I bought an 05 lx from the Midwest with some rusty parts that need some work

I’d like to keep the ahc ideally, but with some of the rust and codes I’m looking at I wanted to see what other members that have gone through this dilemma might think of keeping it or cutting it. System is currently stuck in Low and it’s got a pogo stick ride so I’m guessing bad globes beyond all the codes also.

Codes I’m getting are 1731, 1732, 1733, 1734, 1743, 1711. I would think that because all of the solenoids are firing off codes, it may have something to do with wiring somewhere. Or perhaps that relay code, but I have no idea where to start. Have a front right height sensor but that’s lowest on the priority list as of now.

Found a connector near the driver’s side frame rail that I believe is the control valve assembly? It had black electrical tape wrapped around the wiring that I ripped off. It looks like the previous owner might’ve thrown it on to protect from exposure. Was trying to get it out and get a multimeter on it, but didn’t want to break it yet.

Ahc fluid in the reservoir I think looks okay?

Any one have anything similar to this or perhaps where to start looking when all 4 solenoid codes trigger?

Some other notes, I’m currently wire wheeling and brass brushing and kroiling daily what I can reach on the globes, bleeders, and the torsion bars.

Truck specs: 2005 LX470, ~260k miles, US-spec. Will be living the rest of its life in the desert.

 

[wabiwasabi]

Update on AHC issues:

Popped off BI1 (black, 11-pin connector behind the left rear wheel on the frame rail). Here's what I found:

-Connector pins look clean on both halves, no visible corrosion.
-Readings from the BI1 socket that goes to the valve cover:

• Left 4 pins circled in green: read 8.6 ohms with each other (I believe these would be 2 solenoid coils in a series to give me this reading)
• Middle 3 pins: read 14.1-14.2 with each other (no clue what these are)
• Right 4 pins circled in red: read nothing with each other, nothing against any other pins

What I am thinking from some forum posts and this one from barns with a similar issue: The Blue-Yellow common return wire, is on the right side and is broken between BI1 and the valve block. The 4 signal wires are fine (8.6 reading proves they reach the solenoids). One broken common wire would explain all four solenoid codes (C1731, C1732, C1733, C1734). But I am unsure, if those other 3 on the right are relevant and need to be spliced too?

Solenoids tested good at the valve block at 4.8-5 ohms each.

Before I run a new wire, can anyone confirm: is the Blue-Yellow common the only solenoid-related pin on the right group of BI1? Want to make sure I'm not missing something before I splice.

Also still have C1711 (RF height sensor), and now a C1713 (RR height sensor, appeared after unplugging BI1), C1736 (accumulator solenoid, also appeared after unplugging BI1), and C1743 (main relay, hopefully a cascading issue).

 

[wabiwasabi]

Update: Cut the blue yellow common return line for the accumulator solenoid and 4 leveling solenoids at each end between BI1 and the valve connector. Used a wago 3 wire lever nut at the BI1 junction because it seems in my case, the blue yellow common return loses connection somewhere after it splits off for the accumulator solenoid, leaving only the 4 solenoids at the valve connector without a common return. I needed to run a new wire to the valve connector and still run both ends of the BI1 junction blue yellow cut wire so i could still keep the return running to the accumulator solenoid. This solved all the leveling and main relay codes, was able to raise to neutral.

When I was in netrual, I tried raising it to high a couple times and it failed, went outside and noticed a couple hydraulic lines are leaking pretty rapidly, drained my ahc fluid pretty quick. Both are rear hydraulic lines, one looks like its leaking from a fitting behind the rear passenger globe, and another steel hydraulic line thats super corroded above the rear drivers side globe near, on top of the side frame rail, near the fuel tank cover bracket bolt is leaking pretty bad too. Now to figure out how to fix those, or decide if this is even worth keeping at this point.

 

[Snow Wagon]

Hello wabiwasabi,
Congrats on getting this far
From the greasy pics, I'm guessing the entire underside of the LX was fluid filmed (black version...) or similar, which makes it super fun to work on.
I'm also guessing that the leaks are due to broken / corroded AHC lines, not lines that are mysteriously loose / just need tightened.

I hate to say it, but once you've got multiple lines breaking due to corrosion, IMO it's time to replace the AHC with traditional suspension.
And I love my AHC...

You could pressure wash all of the dirt, fluid film, etc. off the bottom of the LX and see how bad (rusty...) things really are, but then you should probably get it re-fluid filmed.

If you go the traditional suspension route, I'd try to find a used set of 100 Series Land Cruiser Torsion Bars to replace the LX470 Torsion Bars, since Toyota Bars are pricey.
Otherwise, just remove all of the AHC stuff and replace it with your 100 Series Land Cruiser (non-AHC) suspension of choice.

Good luck!
Tom

 

[wabiwasabi]

Hello wabiwasabi,
Congrats on getting this far
From the greasy pics, I'm guessing the entire underside of the LX was fluid filmed (black version...) or similar, which makes it super fun to work on.
I'm also guessing that the leaks are due to broken / corroded AHC lines, not lines that are mysteriously loose / just need tightened.

I hate to say it, but once you've got multiple lines breaking due to corrosion, IMO it's time to replace the AHC with traditional suspension.
And I love my AHC...

You could pressure wash all of the dirt, fluid film, etc. off the bottom of the LX and see how bad (rusty...) things really are, but then you should probably get it re-fluid filmed.

If you go the traditional suspension route, I'd try to find a used set of 100 Series Land Cruiser Torsion Bars to replace the LX470 Torsion Bars, since Toyota Bars are pricey.
Otherwise, just remove all of the AHC stuff and replace it with your 100 Series Land Cruiser (non-AHC) suspension of choice.

Good luck!
Tom

Thanks Tom. That undercoat is an absolute joy in 90 degree weather, especially with the AHC stuck in low haha. I live in the desert so I wouldnt think I'd actually need it, but I bought it from the midwest with it applied already.

Yeah, I really would love to keep the AHC, but my two main concerns now are if I somehow find a way to get these lines replaced reasonably, once the system pressurizes again, I fear new lines will break. Then I'm also worried about slow leaks I probably am unable to see due to the undercoating... I know I should probably just scrap it, it just sucks haha.

My major concern line is the rear drivers side line above the frame rail near the fuel cover bracket, these pictures are probably going to be impossible to decipher with the undercoat, but i was able to poke away a lot of corrosion with a pick at this line:

Theyre both leaking a lot, but this one on the rear passenger side more so, and appears to be at the fitting, however, its so corroded it could be anywhere to be honest:

 

[Snow Wagon]

You're right that in the desert you shouldn't really need it.
But, if there's rust, every time you wash it, or that one day a month that you get 1/8" of rain, it'll corrode a little more...
Is the undercoating soft or hard?
It's difficult to tell from the photos.
If it's the soft stuff, like fluid film, you can wash it off of areas that you're working on.
If it's the hard stuff, you're kinda screwed.

Honestly, you're going to spend a bunch of time (and some money...) fixing those lines, and you don't know what else is going to be wrong with the AHC.
See if you can find a date code on the globes.
Based on your earlier post, I'm guessing they're old / shot.
That's $700+ for the 4 globes and a couple of hours of your time to replace.
Add in 1 height sensor [there's 3 of them...] ($200), the 2 broken lines ($150?), AHC fluid ($50), most likely new AHC Rear Coil Springs ($400), and you're at $1500 + Time.

This Stock Height +1" Traditional Suspension (Front Shocks, Rear Shocks, Rear Coil Springs) is $920 + Shipping, and it's good quality.

Dobinsons Toyota Land Cruiser 100 Series Lift Kit Builder Page

Dobinsons lift kit for Toyota Land Cruiser 100 series, complete suspension kit with all parts needed to refresh your suspension

exitoffroad.com

Go with the IMS shocks (more $...) if you want a suspension that will better handle high speed desert driving (if that's your thing...).

Or, the least expensive (but still good quality...) shocks are probably the OEM Toyota shocks for non-AHC that are around $75 each.

Find a pair of non-AHC Land Cruiser Torsion Bars for cheap on Mud and for $900 to $1200 all in you're driving your LX to Starbucks for cold brew.

Good luck with the process.
If time isn't a factor, and you can wait on parts, I'd order from Amayama (~2 weeks to receive parts) or Impex Japan (~3 weeks to receive parts).

Enjoy.
Tom

 

[wabiwasabi]

Its the soft oily film that gets everywhere, I might spray it off all the ahc lines just to see what I am looking at first. I actually have a set of 4 new globes, a right front sensor, and big silver can of AHC fluid already However, I am still within a return window, just need to decide soon. Perhaps Im looking at the wrong part numbers, but some of these hydraulic lines look quite pricey.

If I can find a deal on some OEM LC torsion bars, shocks, and rear coils on here I might try and jump on them. Im not in a rush, leaving town for a bit, but if I cant find anything nearing my return and I cant price out those AHC lines for cheaper, I'll probably order that dobinson $900 set. Appreciate the resources, going to watch some youtube videos of AHC deletes to see what it entails

 

[Snow Wagon]

It's been a few years since I bought / replaced an AHC line, so the price may be worse than I remember.
It's a very good thing that it's the soft undercoating, as you can clean it off if needed.

Make absolutely sure you are buying non-AHC torsion bars.
When non-AHC owners add an aftermarket front bumper (heavy...), they sometimes switch them out.
Hopefully you can find one locally.

AHC delete is pretty easy (fortunately / unfortunately).
You can leave all of the hydraulic lines / globes / pump in place for now, or you can carefully remove them all.
Toyota / Lexus was nice enough to make all of the mounting points for traditional suspension the same as AHC suspension, so it's really as simple us unbolting your current suspension and bolting in traditional.
The only other thing to do is disconnect the AHC ECM / Computer.

This thread looks to be a pretty good write up.

Thread 'AHC removal / delete experience'

Aug 28, 2014

Here're some things I learnt along the way while removing AHC from our 01 LX470.
I am removing AHC because I am adding front (T13) and rear bumpers (BIOR) and have sliders (OPOR), and I don't want the AHC collapsing on me while exploring far away.

1. Drain the AHC fluid from every AHC bleeder you can find - and the reservoir before removing anything - and you will still spill some, but its not so bad.

2. Put your cruiser on 4 jack stands and you'll need your jack for the rear axle while doing those shocks and springs.

3. Wrenches. I had ordered a 22mm offset wrench from ebay but the...

• LostAfrican
• Replies: 48
• Forum: 100-Series Cruisers

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Enjoy.
Tom