Can you still drive when the AHC fails?

[DocuDude]

I've checked FAQ and Search but I still can't figure out all the info about the AHC.


I have several questions, but most important, if the AHC fails, can the 100/LX470 keep driving indefinitely or once it fails, you are stuck?


How high and low in inches can you adjust?

 

[Ramathorn15]

I've never heard of an AHC system leaving someone stranded. I think the only failure that could possibly impact drivability is if it gets stuck in low. Really the only common failure is with the globes loosing their gas charge (N2 I believe) which results in a rough ride, but thats livable for many many miles if need be.

 

[Ramathorn15]

I also think you get about 1.5-2" in either direction.

 

[DirtDawg]

What @Ramathorn15 said. If the pump fails, you lose adjustability. If you spring a leak, you may be riding on the bump stops for a bit, but you should be able to drive regardless.

 

[planomateo]

With regards to high/low, the owner's manual says:
Low - The vehicle height is about 50 mm (2.0 in.) lower at front and about 40 mm (1.6 in.) lower at rear than the normal mode height.
High - The vehicle height is about 40 mm (1.6 in.) higher at front and about 50 mm (2.0 in.) higher at rear than the normal mode height.

 

[uHu]

You can't go on driving on the bump stops, is that's the issue.
1 - you will break something.
2 - you have no shock absorber function - 1 bump in high speed, or in a curve, and you're out.

 

[DirtDawg]

You can't go on driving on the bump stops, is that's the issue.
1 - you will brake something.
2 - you have no shock absorber function - 1 bump in high speed, or in a curve, and you're out.

You CAN still drive on the bump stops, but not at a normal rate. Im talking like 5mph to limp you to the shop.

 

[Tahomatom]

My AHC Adjusts 2" down for low and 2" higher on High from the N setting.
I just got new 285/75/16's a few weeks ago and measured each setting as my wife goes to see new clients that have unfamiliar parking garages.
I now the height marked at each setting on the drivers visor so she can always fint it.

 

[DocuDude]

So if you were 1,500 miles from home and sprung a leak in the AHC, you wouldnt be able to drive home doing 65mph on the highway?

 

[Ramathorn15]

I assume based on the lack of a listed 100 series in the OP's sig, that he is considering a 100 but is worried about the AHC.

If I'm right, all I can say is if the AHC system is functioning well when you buy the truck, there's no reason to believe it will unexpectedly fail. A friend of mine recently bought a 220k mile LX470 which still has a 100% functioning system. The dealer reports even stated that the previous owner noticed a shop putting washer fluid in the AHC reservoir and took it immediately to the dealer to be flushed out. Washer fluid in the reservoir is the most common source of failure.

As far as leaks go, I've seen maybe 2 reported leaks on here and it was due to massive corrosion of the metal lines. You wont have a leak in a southern CA truck.

Also, if you're planning on lifting at some point anyway, its easy to swap a traditional lift kit in place of the AHC. You can even make some money on the AHC parts you remove if still functioning properly.

 

[DirtDawg]

So if you were 1,500 miles from home and sprung a leak in the AHC, you wouldnt be able to drive home doing 65mph on the highway?

Not unless you repaired the leak or somehow patched it. But the odds of the system leaking are slim to none, the only leaks I have seen are shock failure or a rusted line.

 

[Ramathorn15]

So if you were 1,500 miles from home and sprung a leak in the AHC, you wouldnt be able to drive home doing 65mph on the highway?

Pretty much. Just like if you sprung a leak in your coolant system, you wouldnt be able to drive 1500 miles home, or brakes, or axle seals, or pretty much anything else.

 

[97 AZ LC]

So if you were 1,500 miles from home and sprung a leak in the AHC, you wouldnt be able to drive home doing 65mph on the highway?

No. 5 mph. 300 hours. At 10 hours per day about a month. On the bright side you shouldn't miss any turns or exit ramps. And your passengers will be able to jog along side when they feel like some exercise. Heck even the driver might be able to get in some jogging.