LX570 AHC randomly dropping in normal?? (1 Viewer)

[Dirtracer3]

Does anyone else experience the front end of their LX570 AHC randomly lower slightly when stopped at a stop light?
When sitting it a stop light or pulling into a parking spot, as I sit with my foot on the brake the front end will slightly lower, even while still in normal height mode.
does anyone know why? What is the cause? Thanks!

 

[radman]

Does anyone else experience the front end of their LX570 AHC randomly lower slightly when stopped at a stop light?
When sitting it a stop light or pulling into a parking spot, as I sit with my foot on the brake the front end will slightly lower, even while still in normal height mode.
does anyone know why? What is the cause? Thanks!

This is normal "automatic leveling".

 

[Madtiger]

It is trying to imitate nosedive that us LC owners know well....

 

[TeCKis300]

Yes, some leveling is normal and to be expected, as its an active system.

If you're interested the why:

The act of steering itself can jack the front end because of the caster geometry. That along with side forces on the down angle of the control arms, may cause further jacking when turning in certain situations. AHC will sense this as it has height sensors on every corner, and re-level.

The rear will also re-level in certain situations. Particularly when coming to a firm stop. Perhaps coming a grade, e.g. freeway off ramp. The down angle of the rear trailing arms can also cause jacking of the rear with the application of brakes under these circumstances, which then AHC adjusts for.

 

[Dirtracer3]

Yes, some leveling is normal and to be expected, as its an active system.

If you're interested the why:

The act of steering itself can jack the front end because of the caster geometry. That along with side forces on the down angle of the control arms, may cause further jacking when turning in certain situations. AHC will sense this as it has height sensors on every corner, and re-level.

The rear will also re-level in certain situations. Particularly when coming to a firm stop. Perhaps coming a grade, e.g. freeway off ramp. The down angle of the rear trailing arms can also cause jacking of the rear with the application of brakes under these circumstances, which then AHC adjusts for.

As an engineer, I love your response!

 

[basalt51]

I just test drove a 2014. It lower and raised fairly consistently. But on the test drive, sitting at a stop light on high, the front dropped about 3 inches suddenly enough my wife exclaimed "whoa, what was that". Is that normal? or should it be slower. it caught me off guard as well.

 

[radman]

normal. the real question is why you were you posing in high mode at a stop light??

 

[basalt51]

Ha! Thanks for the confirmation.

I had noticed the front doing its own thing (which now sounds like it leveling itself normally) while testing normal, low, high. So I just left it in high for the test drive to see if it would stay there since it was pretty busy city streets for bit so I wouldn't be going very fast.

 

[OregonLC]

Not sure if this is regarding a sensor-lifted truck, but I feel the height normalization process is more transparent to the operator when AHC pressures are lower. With higher pressures, the momentary release when adjusting down can be feel more abrupt.