Variation in ride height changes all suspension geometry angles including camber, castor, toe, kingpin etc.
The EAS will always try to keep the car at the normal ride height by adjusting the air pressure in each of the four air springs.
In normal mode, there is a certain tolerance range that is accepted by the system and this means that there are tolerable variations in heights between each of the four corners.
The tolerance range in normal mode exists to provide a comprise between system performance and premature wear on the EAS components, especially the solenoid valves.
Under TTM, the tolerance range is a lot narrower and the EAS works overtime to maintain each of the four corners at the normal ride height within this much narrower tolerance range.
In order to get the most accurate alignment possible, TTM must be set to ensure each of the four corners are as close to the same height as possible thereby distributing the total mass of the vehicle across both axles as equally as possible.
If TTM is not set before carrying out the alignment process, there is greater scope for error in achieving the factory suspension geometry angles.
I hope this helps. Kev
2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey
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