LX570 AHC “Basics” - Added as sticky thread for AHC Issues (8 Viewers)

[2014 LEX 570 GA]

Did it attempt to go to HI and not make it? Or no attempt. If no attempt, will it go to HI if you activate it with AHC control?

We’ve seen in the forum where a hidden DTC thrown by AHC system will stop some of the automatic features (in that case he noticed the easy access stopped working).

It did not attempt to go into HI. Truck goes into HI when I manually do it just as it has hundreds of times before, so I do not suspect there is a lack of fluid preventing it from getting up.

How can I search and clear any codes that may be causing this?

 

[lx200inAR]

It did not attempt to go into HI. Truck goes into HI when I manually do it just as it has hundreds of times before, so I do not suspect there is a lack of fluid preventing it from getting up.

How can I search and clear any codes that may be causing this?

techstream Is best option. Possibly something like OBD Fusion with the Toyota Pack.

 

[AnyMal]

It did not attempt to go into HI. Truck goes into HI when I manually do it just as it has hundreds of times before, so I do not suspect there is a lack of fluid preventing it from getting up.

How can I search and clear any codes that may be causing this?

You’re not holding the brake pedal are you?

 

[2014 LEX 570 GA]

techstream Is best option. Possibly something like OBD Fusion with the Toyota Pack.

You’re not holding the brake pedal are you?

No. I was driving around at parking lot speed and it was still in N.

I ordered this but have not installed/setup yet. Can I run tech stream via this?

 

[lx200inAR]

No. I was driving around at parking lot speed and it was still in N.

I ordered this but have not installed/setup yet. Can I run tech stream via this?

View attachment 3281886

You can run OBD Fusion with that, but not Techstream.

You need something like the VCX Nano for Techstream. Or any of the multitude of J2534 cables on eBay/Amazon. Those may just have questionable functionality.

 

[chriscosta416]

I just swapped out my globes and flushed my AHC today, I referenced this video - but ran into an issue during the bleed procedure.


In case anyone runs into this here is what I did to resolve code DTC C1763
(abnormal pump motor oil pressure).




The bleed procedure in the video however did not work for me. The truck threw an AHC error on the dash that I was not able to clear code or error by using the process. The suspension would not go up or down. I plugged in techstream and pulled code DTC C1763 (abnormal pump motor oil pressure). Once I cleared the code I could raise and lower the truck but it was inconsistent in operation. I ran some active tests in TS to verify everything was actually working. Pressure was a hit a miss so either its a blocked line (or I guess air??!)

My first assumption was a blockage and that I introduced or shook up dirty fluid that is blocking a line, but I then proceeded to do the OEM bleeding procedure outlined in the FSM which states to

- Fill up reservoir (I filled it up to the top)
- Bleed Front Driver side
- Bleed Rear Passenger
- Bleed Front Passenger
- Bleed Rear Driver

Check fluid levels and if done correctly you should not have to open up the reservoir again.


This resolved my DTC error and pressures look good. Did a long test drive and changed heights, so far no issues and riding great! I guess if it happens again the next stop would be to open up the pump and check for blockages??

 

[chriscosta416]

Question for all, when opening the AHC reservoir, is it sometimes hard to open and when opening is pressure released? While my LX drives great now I wonder if there is a little bit or air trapped after I drove it

 

[nwfl4runner]

Question for all, when opening the AHC reservoir, is it sometimes hard to open and when opening is pressure released? While my LX drives great now I wonder if there is a little bit or air trapped after I drove it

Yup always for me

 

[AnyMal]

Question for all, when opening the AHC reservoir, is it sometimes hard to open and when opening is pressure released? While my LX drives great now I wonder if there is a little bit or air trapped after I drove it

Never happened to me…

Check that the breather bobs are not seized, it should allow free venting.

 

[lx200inAR]

I believe you are most likely actually releasing vacuum and not built up pressure.

 

[TeCKis300]

Question for all, when opening the AHC reservoir, is it sometimes hard to open and when opening is pressure released? While my LX drives great now I wonder if there is a little bit or air trapped after I drove it

Air in the AHC system IMO is a false premise making it's way around. Unless it's a need to purge air as a result of servicing. The system operates between 1000-2500+ PSI. I believe the system is self purging to a degree and small amounts of air at those pressure are not going to matter.

The reservoir has a breather and is generally going to be at atmospheric pressure.

 

[chriscosta416]

Air in the AHC system IMO is a false premise making it's way around. Unless it's a need to purge air as a result of servicing. The system operates between 1000-2500+ PSI. I believe the system is self purging to a degree and small amounts of air at those pressure are not going to matter.

The reservoir has a breather and is generally going to be at atmospheric pressure.

Gotcha, in that case maybe my breather is clogged not allowing it to vent?

 

[trudd]

Gotcha, in that case maybe my breather is clogged not allowing it to vent?

Experienced the same thing over here when doing a fluid swap. Sounds like normal behavior.

 

[Daniel11]

Good morning,
do you know if it is possible to block the hydraulic suspension in the high position while driving at more than 30 km/h?
THANKS

 

[tbisaacs]

Good morning,
do you know if it is possible to block the hydraulic suspension in the high position while driving at more than 30 km/h?
THANKS

Yes, unplug the height control module but it will drive like garbage.

 

[Daniel11]

Merci pour vos commentaires, où se trouve cette box ? il n'existe pas, comme pour la série 100, le fil d'information vitesse à couper par un interrupteur

 

[TeCKis300]

Good morning,
do you know if it is possible to block the hydraulic suspension in the high position while driving at more than 30 km/h?
THANKS

Using low range will extend the high position to 80km/h (50mph).

The better way to do this if your often running higher speed baja style is to sensor lift. It's not really optimal to be running in high at high speeds as the alignment poor in that mode and it's really meant for obstacle clearance. When sensor lifting and setting up normal for higher clearance and more compression travel, you'll have good alignment for real high speed performance.

 

[tbisaacs]

Merci pour vos commentaires, où se trouve cette box ? il n'existe pas, comme pour la série 100, le fil d'information vitesse à couper par un interrupteur

"Thank you for your comments, where is this box? there is not, as for the 100 series, the speed information wire to be cut by a switch"

How To: LX570 AHC Disable, 20 MPH H Override

This solution stems from all the knowledge that was contributed in @turbo8's thread. With a couple of simple switches you can disable the AHC (essentially locking the truck in whatever height you desire) This will allow you to drive in H over the 20 mph restriction. To me the benefit is...

forum.ih8mud.com

 

[DirtNap]

My driver (left) rear fender is sitting 1.6"+/-0.1" lower than the right at L, N, and H. Having read through a ton of AHC threads over different timelines, is swapping the LR spring for a RR spring still the consensus way to go? I saw TeCKis suggest spring packers at some point. Any pros/cons to either approach?
Thanks

 

[AnyMal]

My driver (left) rear fender is sitting 1.6"+/-0.1" lower than the right at L, N, and H. Having read through a ton of AHC threads over different timelines, is swapping the LR spring for a RR spring still the consensus way to go? I saw TeCKis suggest spring packers at some point. Any pros/cons to either approach?
Thanks

Nah, swapping springs is how you balance the system, the leveling is still done with sensors and techstream.

Not going to comment any more on this though!!! Ive done my screaming. Im an adult now.