AHC LX470 2006 (1 Viewer)

[MooSoo]

Hello everyone,

I am posting this after hours of searching about AHC system (and yes there are too many posts).
My case I am facing (since one year) is little bit different.
I sent the car for dealer, after 2 full weeks, they came up with zero help !!!

To make long story short, the car has been flooded in sea (only up to brake pedal level).
Managed to correct and repair everything (didn't replace harness). Worked perfectly for 9 years.

Last year I started facing AHC system on/off electrical behavior.
When off, all system is turned off, even the lights in dashboard.

While driving it turns on and system is functioning normal.
Lately it started turning on/off badly (i doubt power supply), and finally it went to low level and then not starting up again.
Sometimes, it start blinking fast (like electrical short circuit) then after couple of minutes, it's completely dead.

I am thinking a wire loose connection is main problem, but can't figure out how to start testing connection.

Your support is truly appreciated and I am tend to fix it by myself.

Many thanks in advance. With best regards.

 

[dustbowl]

https://st.club-lexus.ru/attach/u/8f029d8e.pdf



does this help???

 

[PADDO]

To make long story short, the car has been flooded in sea (only up to brake pedal level).
Managed to correct and repair everything (didn't replace harness). Worked perfectly for 9 years.

Last year I started facing AHC system on/off electrical behavior.
When off, all system is turned off, even the lights in dashboard.

Your statement that even the dashboard lights go out tells me that you’ve possibly got an intermittent fault in the AHC ECU power circuits, either the AHC-B fuse, AHC-IG, ECU-B2 or Gauge 1. Loose power to the ECU and you loose all AHC AVS functions including dash lights. These fuses are in the footwell and would be prone to corrosion if you had sea water up to the brake pedal. The fact that you’ve got 9 years after a salt water flood is impressive. You’ll need a copy of the electrical wire diagram (EWD) book that’s applicable to your model and year because you’ll be doing lots of wire, fuse and connector chasing.

 

[PADDO]

https://st.club-lexus.ru/attach/u/8f029d8e.pdf

https://st.club-lexus.ru/attach/u/7558118637071547fc20714a8473c62f.pdf

does this help???

Second pdf is for an air suspension system?

 

[dustbowl]

sorry about that

 

[MooSoo]

Your statement that even the dashboard lights go out tells me that you’ve possibly got an intermittent fault in the AHC ECU power circuits, either the AHC-B fuse, AHC-IG, ECU-B2 or Gauge 1. Loose power to the ECU and you loose all AHC AVS functions including dash lights. These fuses are in the footwell and would be prone to corrosion if you had sea water up to the brake pedal. The fact that you’ve got 9 years after a salt water flood is impressive. You’ll need a copy of the electrical wire diagram (EWD) book that’s applicable to your model and year because you’ll be doing lots of wire, fuse and connector chasing.

Wow this is exactly what I was looking for . .
Can't thank you enough.
Wish if there is any image or hint showing where exactly AHC-B, AHC-IG and AHC-B2
I will start checking the fuse box under driver side and will post updates.
Thanks millions again.

 

[PADDO]

The two AHC fuses are in the left footwell junction box, as is the gauge fuse I mentioned. ECU B fuse is in the right footwell J/B. There’s diagrams showing fuse ID and ratings printed on the insides of their black plastic fuse covers and it’s also in your owners manual too.
There’s no guarantee this is the root of your problem but for what seems to be an intermittent loss of AHC ECU power checking/cleaning/reseating fuses is a good place to start, particularly in light of the fact you had a salt water soaking. Hope this helps.

 

[MooSoo]

Hi, spent weekend tracing wires and sockets, unfortunately still issue there, however, i can say the issue is linked to AHC-IG. When I remove that fuse, system stop blinking and switch off, when I reconnect, it back for short blinks. This is not happening with AHC-B.
Now if can someone kindly direct me to electrical diagram similar to attached. I got 2002 and 2003 but can't find 2006.
Will keep you updated. Very hectic but exciting work with each small progress.
Also, is there anyway to remove fuse box in both sides footwell! Can't see anyway to remove them!!!
One last request, is there any manual way to adjust height of the car (plan Z, thinking of disabling system after fixing height properly, now left side of vehicle is higher than right).

 

[MooSoo]

Dear members,

Kindly anyone can help telling me how to control height manually, pls.!
Many thanks.
Regards.

 

[uHu]

With the AHC system in place there is no way to control the height manually. It's an active system, if it doesn't work, you can't drive (safely and comfortably). You options are either to fix the ahc or change out the springs and shocks for non-ahc parts.

 

[MooSoo]

Thanks uHu, at the moment, I managed to get right height and I unplugged sockets from AHC-ECU.
Looks like its dead now and will not act funny while driving.
Thanks again. With best regards.
Wish to find right electrical diagram.