AHC Malfunction

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ntsaint

ntsaint

Don't Assume I Know The Basics...
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So my ride has been getting a little stiffer lately, thought i would look into testing the AHC 'travel' and then flush the system.

However, small problem...AHC won't change positions. It's in Normal mode, but when i try to move it to H or L, the light just flashes a couple times and nothing ever happens...

Anyone ever have this happen before?? Any ideas?
 
That means its time for an OME lift lol I'm jk We have one AHC vehicle at home, its a gx470. I had this problem with ahc but usually its a temporary problem...then one day I adjust it and its working again...its magic
 
LJ_24 said:
That means its time for an OME lift lol I'm jk We have one AHC vehicle at home, its a gx470. I had this problem with ahc but usually its a temporary problem...then one day I adjust it and its working again...its magic
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Thanks. I hope 'magic' is the issue here. I just used it last week, worked fine. Will try again tomorrow.

Really don't want to do the OME, etc, until this is no longer my daily driver...
 
Maybe the system "thinks" that the e-brake is disengaged, or one of the doors is open, or it's not in park or something like that... I know that with mine, I have to have all those things in order before it will respond... (unless your override switch changes that too)... Just a thought...
 
arbetrader said:
Maybe the system "thinks" that the e-brake is disengaged, or one of the doors is open, or it's not in park or something like that... I know that with mine, I have to have all those things in order before it will respond... (unless your override switch changes that too)... Just a thought...
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Wish this was it, but tried the brakes, e-brake, etc.

Guess I'm going to call the folks at Slee, see if maybe i have a bad switch...
 
OK, nothing is working. And worse, doesn't appear that the suspension leveling is working, and the ride is rough and stiff.

I guess I'm going to take it into the dealership. I bought the 100k warranty from Toyota, maybe this will be covered...
 
ntsaint said:
OK, nothing is working. And worse, doesn't appear that the suspension leveling is working, and the ride is rough and stiff.

I guess I'm going to take it into the dealership. I bought the 100k warranty from Toyota, maybe this will be covered...
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Where in Louisiana are you? I just brought mine in to a dealership in BR, for essentially the same problem, and not too much was accomplished.

BTW, you have the inverse of my car with the same nice plate in the front.
 
Joebu33 said:
Where in Louisiana are you? I just brought mine in to a dealership in BR, for essentially the same problem, and not too much was accomplished.

BTW, you have the inverse of my car with the same nice plate in the front.
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I'm in north Louisiana...Monroe. Dealership here sucks. Gonna take it to Shreveport next week. They have a good LC mechanic there.

What symptoms were you having? And what did the dealership say?

Love my LSU plate...I rotate it with my Saints plate every few months!

Throw up some pics of your truck!
 
ntsaint said:
I'm in north Louisiana...Monroe. Dealership here sucks. Gonna take it to Shreveport next week. They have a good LC mechanic there.

What symptoms were you having? And what did the dealership say?

Love my LSU plate...I rotate it with my Saints plate every few months!

Throw up some pics of your truck!
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My AHC "Off" light would come on every now and then, and the AHC system wouldn't function at the time. The ride overall also seems rougher than it used to be.

Here's a couple of photos for ya (first one's from the phone, so it's not the greatest).
IMG_0866 (800w).webp
IMG_0618 Cooper Zeon LTZ 800w.webp
 
Joebu33 said:
My AHC "Off" light would come on every now and then, and the AHC system wouldn't function at the time. The ride overall also seems rougher than it used to be.

Here's a couple of photos for ya (first one's from the phone, so it's not the greatest).
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Great lookin truck man! What make model and size are those tires?
 
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Joebu33 said:
Thanks! The tires are Cooper Zeon LTZ in a 285/60/18 flavor. I like 'em.

P.S. - Sorry the Tigers put a whoopin' on your townsfolk!
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Love those tires....I'm due for a new set next year and those just moved up the list.

I'm purple and gold all the way through man, could care less what ULM does. They need to move back to FCS level anyway.
 
I'm guessing you know this and tried it already, but from what I've seen if you to make the change and see it happen (i.e. not while driving) then you need to make sure engine is on, all doors are closed, you're in park, and that your foot is not on the brake pedal and then when I switch to H/N/L it changes.

Again, probably not news to you, just making sure 'cause that would be an easy explanation.
 
FWIW, we did speak on the phone about this. I would take the AHC controller out of the circuit to make a 100% sure it is not affecting the system. Probably a good thing to do before taking it to the dealer, since they are just going to blame it.

The board disables the automatic lowering, but should not affect the overall operation.

Also for anyone installing this, it is good to install things like this with a connector, so that a "jumper" connector can be made to quickly remove the system and put it back to stock. Good practice for any type of box / circuit that is installed into a truck.

mouser.com sells good Molex type connectors.
 
AHC diagnostics run them first

I am surprised no one has suggested reading the error code. All the diagnostics ---the very same ones a Dealer Tech can run with the 'hand held computer' are built in to the AHC computer. You need only jump 2 connectors in the diagnostic port and then push buttons. If anyone want jpg photos of the relevant pages from the Lexus Repair Manual, send me an email.

Sharing of these photos with individuals IS a permitted 'fair use' under copyright laws, but 'posting' them is a questionable act.
 
Texasoil said:
I am surprised no one has suggested reading the error code. All the diagnostics ---the very same ones a Dealer Tech can run with the 'hand held computer' are built in to the AHC computer. You need only jump 2 connectors in the diagnostic port and then push buttons. If anyone want jpg photos of the relevant pages from the Lexus Repair Manual, send me an email.

Sharing of these photos with individuals IS a permitted 'fair use' under copyright laws, but 'posting' them is a questionable act.
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Yes, would love to see that. PM sent with my email address.
 
Any luck in resolving your issue? Unfortunately I think I am looking at something similar with my '06 LC and am curious to see how your issue is progressing.
 
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