LX570 AHC “Basics” - Added as sticky thread for AHC Issues (1 Viewer)

[lx200inAR]

So, recently my AHC pump broke leaking all the fluid in one go, and my local Lexus dealer gave me a huge quote for the pump replacement. I decided to buy the pump assembly and AHC fluids off ebay and have my local mechanic replace it to save on costs, as I'm not handy with car repairs myself. My mechanic replaced the old pump with a new one, but now only the left (driver) side rises up. He can't figure out why the right side won't work. For context, when showed it to Lexus dealer originally, they said my rear right sensor was seized and they replaced it. Any ideas what might be wrong here? I really don't want to take it back to the dealer

You most likely need to get Techstream to see what’s going on with the AHC eCU. Trying to tshoot this with some many variables most likely won’t be fruitful.

 

[grinchy]

Glad the new pump is already primed, that’s usually a hurdle.
This could just be a need to bleed again as well.

 

[misteracng]

I performed AHC flush on my LX570, 32k miles, 2021 model. It was simple with the instructions. I filled up the tank with about 2 liters then flushed. Driver front first twice, started the car to let it rise after each drain. Only did the passenger front one time, as it was pretty clear. Same for the rear. I used about 4 liters total. Fluid was dark already but not as bad as some of the pictures in this thread. A short stubby 100mm wrench for the rear bleeders is essential.

 

[fcigoj]

Nope - should be near max when you’re in low

Sorry to interject, but by reading earlier posts in this thread I understood that the level should be at Max when in Normal position. If that is correct it should be well above Max in Lo. Can someone confirm my correct understanding ?

 

[LXCruza]

Sorry to interject, but by reading earlier posts in this thread I understood that the level should be at Max when in Normal position. If that is correct it should be well above Max in Lo. Can someone confirm my correct understanding ?

I believe in Normal mode it should be somewhere between Min and Max.

 

[fcigoj]

I just finished reading through the 41 pages, and it has been extremely informative. Thanks to everyone who has contributed to this wealth of knowledge.
Now, my question is the following: having to replace the fluid AND the accumulators, should I replace the fluid first to avoid contact of the new accumulators with the degraded fluid, or it´s no bother ?
My paranoid approach would be to flush the central accumulator and the four corners twice first, then replace the accumulators and purge air the third time. It requires a lot of work and fluid but...
Grateful for any input

 

[misteracng]

I believe in Normal mode it should be somewhere between Min and Max.

That is correct based on TIS, in normal hieght mode. It is however fine to have extra, maybe at max or slightly above, there is plenty of capacity in the tank, and will allow more margin in case there is some fluid loss.

 

[misteracng]

I just finished reading through the 41 pages, and it has been extremely informative. Thanks to everyone who has contributed to this wealth of knowledge.
Now, my question is the following: having to replace the fluid AND the accumulators, should I replace the fluid first to avoid contact of the new accumulators with the degraded fluid, or it´s no bother ?
My paranoid approach would be to flush the central accumulator and the four corners twice first, then replace the accumulators and purge air the third time. It requires a lot of work and fluid but...
Grateful for any input

I think you can just drain the corner and replace the globe, then flush for air and old fluid a few times till you are satisfied. That is what I have seen. It would seem to be a large use of fluid to do it before and after.

 

[rherrco]

Nothing wrong with that. You'll also have to look at the other parts and how you're going to package this all in. Meaning there's limited width before going past the fenders. Compression travel is pretty deep and puts even a 33" well under the fender lip. With 1.5" wider tundra arms, and necessary offset (another 1-1.5" to clear suspension and frame, you'll have to

 

[rherrco]

Last post was a screwup.
However, I have been reading and re-reading this thread trying to determine if I need to either flush or replace globes and then flush my AHC. Or leave it alone. My situation is a 2011LX with 125k. Ride quality is not real tight, some shuddering over small bumps/holes, especially when vehicle is empty. Loaded up or Offroad it feels better. Also the switch for suspension control does nothing noticeable. The manual height control works reasonably well. My local Toyota repair shop is not helpful. Reservoir fluid level is on the low side and looks on the darker side. I’m unable to determine when it was last changed, but think it’s due. Question is will replacing the globes help with ride quality or is it maybe an actuator problem.
I’ve seen posts with others in the same boat but have not seen a consensus of opinion on results of which way to go. I only drive it a few thousand miles a year mostly to go off road exploring, and I can live with the current ride quality, but being retired and reading ihmud is a dangerous combination when it comes to tinkering with my LX. Any suggestions from those more knowledgeable would be appreciated.

 

[paulunm]

Last post was a screwup.
However, I have been reading and re-reading this thread trying to determine if I need to either flush or replace globes and then flush my AHC. Or leave it alone. My situation is a 2011LX with 125k. Ride quality is not real tight, some shuddering over small bumps/holes, especially when vehicle is empty. Loaded up or Offroad it feels better. Also the switch for suspension control does nothing noticeable. The manual height control works reasonably well. My local Toyota repair shop is not helpful. Reservoir fluid level is on the low side and looks on the darker side. I’m unable to determine when it was last changed, but think it’s due. Question is will replacing the globes help with ride quality or is it maybe an actuator problem.
I’ve seen posts with others in the same boat but have not seen a consensus of opinion on results of which way to go. I only drive it a few thousand miles a year mostly to go off road exploring, and I can live with the current ride quality, but being retired and reading ihmud is a dangerous combination when it comes to tinkering with my LX. Any suggestions from those more knowledgeable would be appreciated.

Definitely do the globes and fluid. 10 years or 100k miles is about what they last IMO.

 

[rherrco]

I figured I was just waiting for someone to say that. Now rear I’ve ordered the globes there’s no going back. AHC fluid is next. I saw an older post where someone had listed very detailed steps for changing globes and fluid. Can someone point me to the right page or link? I don't think I want to mess with that #5 actuator bleed screw, and I’m definitely not a tech stream guy. Thanks.

 

[rherrco]

As luck would have it I managed to install both front globes in the rear and rears in the front. The only way to tell them apart is the suffix on the stamped serial number, shown below. Many thanks to the folks at jdmparts/old-rarity-japan who responded to my request for guidance, since no part number is listed on the actual parts. H is for the fronts and L for the rears.

 

[04UZJ100]

As luck would have it I managed to install both front globes in the rear and rears in the front. The only way to tell them apart is the suffix on the stamped serial number, shown below. Many thanks to the folks at jdmparts/old-rarity-japan who responded to my request for guidance, since no part number is listed on the actual parts. H is for the fronts and L for the rears.

View attachment 3729423

View attachment 3729424

Aren’t their part numbers on the boxes themselves?

 

[rherrco]

Aren’t their part numbers on the boxes themselves?

Not on the OEM ones I bought. Whoops, yes on the boxes, no on the actual parts.

 

[poppe]

So long story short, my rear passenger sensor bracket was adjusted to highest bracket setting and all other sensors are normal stock. Do I put the car in high mode, crawl under and adjust the one sensor back to normal by eyeing it - and do I need to worry about the vehicle dropping when I do this?

 

[rherrco]

So long story short, my rear passenger sensor bracket was adjusted to highest bracket setting and all other sensors are normal stock. Do I put the car in high mode, crawl under and adjust the one sensor back to normal by eyeing it - and do I need to worry about the vehicle dropping when I do this?

It depends on how your truck is sitting. If the rear fenders measure the same height off the ground, why adjust? Fronts should measure the same side to side, but lower than the back. My right front sensor is all the way up, while the left is mid range. But the truck is level. I think Lexus considers 1/2” variance close enough.

 

[poppe]

It depends on how your truck is sitting. If the rear fenders measure the same height off the ground, why adjust? Fronts should measure the same side to side, but lower than the back. My right front sensor is all the way up, while the left is mid range. But the truck is level. I think Lexus considers 1/2” variance close enough.

Basically, a friend hooked me up with a tire deal at his tire shop. But then because they thought the tires would rub they messed with the sensors (frustrating for sure). Put all back they said, but they weren’t 100% - so I’m assuming the sensor needs to be even with the other rear sensor as the whole vehicle now rides insanely awful. Super bouncy ride, every bump, even the smallest feels uncomfortable. I plan on getting an alignment too since it went to bigger tires. I crawled under the LX and all sensors matched what I’ve seen online except for the rear driver side. That one looks like if you did the sensor lift, fully pushed up.

The Rear driver side is now sitting higher than all the other wheel wells - at least on the eye test. My LX has always seemed to sit pretty even but now it looks like it’s sitting tilted when you look on the driver side at profile.

 

[rherrco]

I don’t think the sensors have anything to do with the ride damping, but I would measure the height of the fender lips and adjust accordingly. Easy to do with two 10mm wrenches.

 

[poppe]

I don’t think the sensors have anything to do with the ride damping, but I would measure the height of the fender lips and adjust accordingly. Easy to do with two 10mm wrenches.

Copy. Sorry I’m kind of dumb with this stuff. What part of the fender am I measuring and to what?

Only thing I can think is I got a set of 17” rims and wheels at 285/70/17 they mentioned the sensor adjustment and then putting back. And now the ride rides remarkable worse. Sort of shaky and bouncy, especially on freeway. And drives super straight.

All sensors look normal compared to videos except rear driver side that is pushed all the way up. So that’s what had me thinking to move it to center.