05 lx470 AHC failure? bouncy ride (1 Viewer)

[MastiffDad14]

Bought a sight unseen lx470 with 71k miles, anyways truck is absolutely beautiful frame body interior but the suspension leaves much to be desired.

The height control works, but the 2 comfort settings and sport setting doesn't change anything.

The second you hit a bump the car just bounces down the road it feels like it's coming from only the front but hard to say as I only drove 20 miles today.

Am I dreaming if I think that flushing the AHC fluid might fix the problem? Tomorrow I'll count the marks from the low to high setting and report back. Anything else I can check before caving in and getting accumulators?

 

[FxFormat]

Chances are your accumulators are shot, they are very expensive to replace at the dealership. Try to get it from online and have a local mechanic that knows this truck do it. Mine went out, I don't think flushing will do anything, you can try, doesn't hurt.

 

[PLROD]

your accumulators are shot; I have the same issue right now that i'm trying to resolve...flush and replace the fluid only if you've decided to keep and repair the ahc - it will not fix your issue though.

 

[MastiffDad14]

Well I guess I can only hope it's just the fronts, not all 4.

 

[FxFormat]

My front went out, fixed that, months later, rear went out, fixed that too. So far so good, i just got an 01 LC to play around with, got the bug after looking at some pics on this forum.

 

[MastiffDad14]

Ok here's an update.

AHC does not go from L-N-H anymore just satays in N position. It seems to be self adjusting at stop lights or when Im sitting idling somewhere. The front end will drop down what feels like 6 inches and then raises back up then drops down maybe an inch or 2 I assume it's just leveling it self out.

Next the AHC OFF light flashes periodically when driving, I turn it off when ever I get in the truck and it stays solid OFF for maybe a minute or two then begins to flash for quite some time. Next thing you know the OFF light is not flashing and that's when it does its dropping and raising to level again. If I push the off button it stays level.

The ride is not as bouncy as when I first first bought the truck last week, still very far from ideal but before I felt like my head would hit the headliner now it just feels like a car that has extremely bad shocks.

I'm sure it's the accumulators / globes that are bad, but I wanted to post here first since now it will not allow me to cycle through height adjustments.

 

[2001LC]

Ok here's an update.

AHC does not go from L-N-H anymore just satays in N position. It seems to be self adjusting at stop lights or when Im sitting idling somewhere. The front end will drop down what feels like 6 inches and then raises back up then drops down maybe an inch or 2 I assume it's just leveling it self out.

Next the AHC OFF light flashes periodically when driving, I turn it off when ever I get in the truck and it stays solid OFF for maybe a minute or two then begins to flash for quite some time. Next thing you know the OFF light is not flashing and that's when it does its dropping and raising to level again. If I push the off button it stays level.

The ride is not as bouncy as when I first first bought the truck last week, still very far from ideal but before I felt like my head would hit the headliner now it just feels like a car that has extremely bad shocks.

I'm sure it's the accumulators / globes that are bad, but I wanted to post here first since now it will not allow me to cycle through height adjustments.

I'd not be so sure globes are bad at 71k on an 05. I worked on an 01, 00 & 98 w/215, 270 & 300K miles with what may have be factory fluid still in AHC reservoir. All were low and raised and lower at stops. Once flush they worked fine. For $35 it's worth a try.

 

[cwininger]

If you decide to replace AHC components it's a job you can probably do yourself if you are even remotely mechanically inclined. LX 470 Suspension Accumulators | Nitrogen Globes | Land Cruiser Damping Globes Has good prices on replacement components and will provide tech support during your install.

 

[Dannyboy lx470]

Just a question is there suppose to be a huge difference when you switch between comfort and sports in ride ??.Do you hear anything when you switch.One thing I noticed my tyres were low in pressure and once I pumped them up the car felt alot better.

 

[MastiffDad14]

No noticeable difference and also the height control doesn't work. Other than the random self leveling.

Just a question is there suppose to be a huge difference when you switch between comfort and sports in ride ??.Do you hear anything when you switch.One thing I noticed my tyres were low in pressure and once I pumped them up the car felt alot better.

 

[PADDO]

You only replace the damper globes as a last resort - not the first.
You've described classic height sensor failure symptoms so that's what I'd focus on initially. Self leveling should be very small adjustments, not large, and it's likely the system has/is faulting itself and locking out height control for self protection.
Get yourself Techstream and the AHC FSM sections so you can see and understand what the system is doing, height position feedback, your pressures (crucial for optimum damping) and any DTCs.
Do your low to high test but for those results to be true your neutral pressures must be satisfactory, but if you only return three or four grads then one or more damper accumulators are likely done. Do the 16 step damper test to try and isolate a defective damper - it's the technical way of approaching a defect; driving off a curb bounce test is pretty much pointless. The 16 step test also allows you to lock the system in softest and drive to help determine if you have a mechanical/hydraulic issue or an electronic control issue.
If you ultimately elect to fit new damper globes then it's a 1/2 hour job that when done in the easiest manner just needs a can of fluid for topiping up and a 36mm thin wrench (Ford 36mm fan clutch wrench from autozone or wherever is perfect).
Find the "definitive AHC maintenance thread" and read backwards as it's too long, but there is some good tech advise there.

 

[H E A V Y M E T A L]

The amount of money to repair your aging failing system you can buy a very nice lift kit once and for the most part the duration of ownership. Or you drop that coin fix the ahc problem and next month another $1300 repair just to keep it.

 

[MastiffDad14]

I am on the fence, if I feel like going through with fixing the suspension or going with an OME 2.5" lift through Slee.

 

[H E A V Y M E T A L]

Man I was in the same spot as you and I just decided- since I wheel it, take the ahc off.

But your system may be in better shape then mine was. Whatever, keep me in the ahc loop. good thread.

 

[Dannyboy lx470]

When you say replace the suspension with a alternative instead of fixing the ageing one $$$ do you mean new shocks and springs thats all cause I'm not really going offroad just want it standard and a nice ride.If you do this the AHC system wont function no more so will the sports and comfort control for the shocks right ??.

 

[H E A V Y M E T A L]

When you say replace the suspension with a alternative instead of fixing the ageing one $$$ do you mean new shocks and springs thats all cause I'm not really going offroad just want it standard and a nice ride.If you do this the AHC system wont function no more so will the sports and comfort control for the shocks right ??.

Oh great point if your not wheeling the ahc system is one of the best dynamic adjusting systems out there hands down.

 

[Dannyboy lx470]

Maybe someone can expand on it if it still works the shocks adjustment switch if you install new shocks or springs.I'm guessing the AHC system wont.

 

[Julian Stead]

Maybe someone can expand on it if it still works the shocks adjustment switch if you install new shocks or springs.I'm guessing the AHC system wont.

If you put standard shocks on it won't work. You need to follow PADDOS advise if you want to get your AHC back up and running correctly, read his previous posts and get a better understanding on how it works. The price of repairing and servicing this system has dropped a lot in the U.K., it is cheaper to repair than to replace now most of the time. If you you don't understand it you can't expect to repair it, it isn't complicated it is just different to standard suspension.

 

[Stricmic000]

Sooooooo what happened?

 

[MastiffDad14]

Sooooooo what happened?

Couple issues, front pressures were out of spec magnifying the bad globes. When I posted again on Dec 17 about the Ahc flashing i noticed a broken wire going to the passenger height sensor.

Path that ultimately fixed it:
Fixed height sensor wire, flushed out old AHC fluid adjusted torsion bars. - still had a bouncy ride (front globes were shot)

Bought 4 non OEM globes from a European manufacturer. After replacing all 4 globes the truck rode like new. (Currently have globes and other AHC components in the garage)

Ended up removing the AHC system due to adding a bunch of weight (Tjm front bumper w/bull bar, 12k winch, Dobson rear drawers, dometic fridge and a slee dual swing out rear bumper.)

While the AHC system could handle the weight, I was in a position to buy a Tough Dog suspension kit and I went for it. Couldn't be happier, truck feels extremely planted and handles the additional weight wonderfully.