1200 miles trip and issues with AHC.

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Another interesting thread regarding the dreaded AHC.

Anyway, I had this exact same thing happen to me. I have an '06 LX with about 35k miles. Earlier on this year, I had 8 passengers, including me- of course. I would say, weight capacity of each passenger varied from around 150lbs to 250lbs. Average weight maybe ~200lbs. Give or take.

Oh boy, the moment I started pulling out of the driveway, I could see the Height Control Lever on my instrument cluster switching between 'L' and 'H' constantly. I turned the car off, fired up again and it sat on 'L'. I drove like that for about a couple of hours.

Next day, the car went back to 'N'.

However, a month later, my rear height sensor failed on me. Rear of the car was sitting way high and the car drove as if it lacked shock dampening. Not quite sure whether the height sensor failure was attributed due to the weight overload or maybe due to normal wear/tear.

Nonetheless, I had the height sensor replaced and all is good now. But I swore to my self never again will I ever drop my third row seat. The only exception to the rule would be if passengers on the third row seats are toddlers. :)
 
r3run33 said:
Hello my $.02 input in 2006 toyota began using "out source parts" for the AHC; for our year 2006 actually has a TSB put out. With your low miles, you may want to check to see if it was done. I had trouble with mine and had it switched out under warranty but now that I am out of warranty its coming out. I have a 2006 LX470 and did some research back then when I had lots of trouble. Denso did not make the OME parts when our vehicles where made. Now I'm not sure if the TSB used different parts but I will say after my system was fixed I did not have the same issues.
Click to expand...

Which TSB are you referring to and what issues did you have that were fixed by the TSB?
 
r3run33 said:
Hello my $.02 input in 2006 toyota began using "out source parts" for the AHC; for our year 2006 actually has a TSB put out. With your low miles, you may want to check to see if it was done. I had trouble with mine and had it switched out under warranty but now that I am out of warranty its coming out. I have a 2006 LX470 and did some research back then when I had lots of trouble. Denso did not make the OME parts when our vehicles where made. Now I'm not sure if the TSB used different parts but I will say after my system was fixed I did not have the same issues.
Click to expand...

How would i find out if it's Denson or TSB?
 
For PK470: overload will not damage the height sensors. With only 35k miles that sounds like either a bad or badly installed (i.e. loose screws) part.

Given your symptoms probably a bad sensor returning erratic readings.

I am also interested in that 2006 TSB fwiw
 
Sensor is a manufacturer of the AHC control parts for many of the Toyota/Lexus models; I think 2006 and 2007 they out sourced the parts to another company. If you research the Toyota TSB you should be able to find it. If I remember right the TSB basically tested the AHC and replaced the spheres and some other things if they failed the test. I'm at work but tomorrow I will try to pull my service file and see if the TSB is listed. But I think you maybe able to go thru the government highway site a see it there.
 
Sorry that is incorrect





autosmash.com/tsb/TSB_LEXUS_LX470...
NHTSA* TSB Technical Service Bulletin Number: 10008390 Bulletin Date: ..... ALL LEXUS 2002 - 2006 MODELS. ... A FLASHING AHC (ACTIVE HEIGHT CONTROL) OFF LIGHT WITH ...

Here is another
 
thanks, very helpful info. I'm going to check with the dealership to see if they'll take care of the TSB.
 
I found if the AHC will not rise after loading the car with passengers and cargo then kick the passengers out and with the lowered weight the LC/LX will rise, then have the passengers reboard. Only happened twice but worked both times.
 
I'm interested in finding out if there's a TSB I may have missed.

Though I do not worry about Toyota (or Lexus) 'outsourcing' as you put it. Many parts to any car are sourced from suppliers, but the difference is that they must meet toyota requirements for performance and reliability requirements, or in Lexus's case, even higher requirements.

For the AHC system, it's important to 'tune up' and adjust the neutral pressures on the system especially for an older hundy. As the metal springs sag as they do on all vehicles, the AHC will support proportionately more weight. This will effectively reduce the weight carrying capacity of the AHC - especially it's capacity to maintain neutral and high heights when carrying significant weight.

I've adjusted system and posted about it here - https://forum.ih8mud.com/100-series-cruisers/656163-ahc-neutral-pressure-adjustment.html

One can actually setup the system to carry wight beyond, or at least slightly beyond what it's rated for, by shifting some more of the static weight to the metal springs, and reserving more AHC capacity for when it is loaded down.
 
this was an old tread which I gave up on; I love my vehicle but your comments of toyota or lexus having high standards are wrong. its all about the money and how to save it. with 06 and 07 model years they pinched a lot . Honestly I dont think the parts used when production was done are being used anymore. Thats just my opinion; the TSB probably told the tech to look for any problems and then replace even if the system was working fine. another issue is the VGRS system which I am surprised not more people posting issues with here.
 
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