Thread: Wheel Alignment for D3/D4/RRS is not that simple!

Originally Posted by DieselLSE

Vehicle height changes are restricted if the air suspension control module receives a 'Door Open' signal and the speed is less than 5 mph (8 km/h)

Door Open Inhibit Mode
If one or more of the vehicle doors are opened during a height change when the vehicle is stationary, the air suspension control module will restrict further height change.The LED on the air suspension LED display for the target mode height will remain illuminated and the raising or lowering LED will flash.If all of the doors are closed within 90 seconds, the height change will resume. If the 90 second period is exceeded,the message 'CONFIRM REQUIRED SUSPENSION HEIGHT' will be displayed in the IC.

This refers to physical height changes such as changing from onroad to offroad height or lowering etc via the console switch - it does not apply to self leveling functions.

Having seen it do it on several vehicles I wouldn’t rely on it.

And as mentioned with a potential of up to 20mm variance in height I wouldn’t be aligning it like that either.

Originally Posted by Tombie

Having seen it do it on several vehicles I wouldn’t rely on it.

And as mentioned with a potential of up to 20mm variance in height I wouldn’t be aligning it like that either.

I don’t think anybody has ever mentioned or knows this and it could be pure conjecture on my part.

During normal operation the car tries to level relative to the surface that its sitting on. Is that correct?

In order for TTM to get as close to the null point as possible, it would have to be effectively referencing to itself (car), regardless of the terrain, wouldn’t it?

Which practically means when movement is forced to stop by means other than TTM you could have all 4 legs as much as 20mm from the null point, in either direction I suppose .... with a total potential complete separation of 40mm between two wheels. That can’t be great for the wheel alignment.

This thought has only occurred to me and it maybe completely wrong LOL!!!

Thoughts?

I have read this in several places in LR’s own material.

Opening the door during a height change (i.e. when it is changing to a new height) will stop the height change.

However, levelling (which is technically not a height change) can still take place even if the door is open.

Leaving the door open does not stop self levelling.

Originally Posted by Celtoid

I don’t think anybody has ever mentioned or knows this and it could be pure conjecture on my part.

During normal operation the car tries to level relative to the surface that its sitting on. Is that correct?

In order for TTM to get as close to the null point as possible, it would have to be effectively referencing to itself (car), regardless of the terrain, wouldn’t it?

Which practically means when movement is forced to stop by means other than TTM you could have all 4 legs as much as 20mm from the null point, in either direction I suppose .... with a total potential complete separation of 40mm between two wheels. That can’t be great for the wheel alignment.

This thought has only occurred to me and it maybe completely wrong LOL!!!

Thoughts?

You're overthinking this Celtoid.
We're talking wheel alignment here and you're not going to attempt that half way across a paddock. At some stage before the wheel alignment, and this could be miles away perhaps, you set the suspension to TTL. There'll be a warning on the dash that the car is not in customer mode or something but the car will drive to the alignment place quite OK. At the aligners they will place the car on a supposedly level surface and the car will level itself to within 3mm of spec at each corner. It should then be sitting as perfectly level as it can. It will adjust itself as the driver exits or whatever. Thus the alignment will be as accurate as possible.
After the alignment, reset it back to normal mode.
I make sure I have the main tank full and auxiliary tank half full and that the car is loaded with what I normally have in it before doing an alignment.