How does the car know if it’s level?

[Lukeis]

Hi all

does anyone know what the car uses to think it’s level or not? Is there a gyroscope?

I have a D4 which is dropping in the front end, but when I remove the fuse in the engine bay the car doesn’t go anywhere.

whereas if I leave the car unlocked I can literally watch it drop, but it’s doing it deliberately like it’s trying to level the car (but it’s already level).

Im wondering how it knows it’s on a slope? Any ideas what it could be?

[josh.huber]

Looks at each height sensor to make a decision on what to do.
So if the front left was to high, as in was at 400mm instead of 360mm it'll adjust for that. It's not too level the car from a bubble point of view.

I believe I read it will make adjustments for anything outside of 10mm from set point.

In my experience, the car did it allot less with new shocks, I believe because there was no dampening the car would compress the strut more on a bump and add more air into the bag to get the ride height right when under way. When I parked the front would drop at least 30mm. The shocks were completely useless by that point but.

Use your gap tool to see what your corners are doing when you pull up. Then see what they drop too.

[101RRS]

It measures via the height sensors to ensure it is parallel to the surface it is on, not the horizontal in a spatial sense. So on my relatively steep drive it adjusts to slope not the horizontal.

[Eric SDV6SE]

Hi all

does anyone know what the car uses to think it’s level or not? Is there a gyroscope?

I have a D4 which is dropping in the front end, but when I remove the fuse in the engine bay the car doesn’t go anywhere.

whereas if I leave the car unlocked I can literally watch it drop, but it’s doing it deliberately like it’s trying to level the car (but it’s already level).

Im wondering how it knows it’s on a slope? Any ideas what it could be?
Taking the fuse out doesn't do anything other than stop the power to the solenoids that control the valve blocks. The car will "level" to be parallel as possible to the surface its on, within limits of the range of motion allowed by the ecu. From your post I read that the height calibration may be out and needs to be reset. A GAPiid tool or similar will allow you to do so.

[ramblingboy42]

if this gap tool is so important to the functioning of this vehicle , why wasn't it built in to it?

More of the reason I don't or cant justify owning one.

the d2 was bad enough but my local indy let me do any scans free in their workshop....still do.

[PerthDisco]

if this gap tool is so important to the functioning of this vehicle , why wasn't it built in to it?

More of the reason I don't or cant justify owning one.

the d2 was bad enough but my local indy let me do any scans free in their workshop....still do.

It’s like owning the dealership workshop for a few 100$. Instead of them raking in the easy $$ reading the diagnosis and changing a part you do it and pay the tool back almost immediately. Plus you have the peace of mind in a remote scenario of making a simple fix or working out a problem.

I replaced a clock spring for $300 self diagnosed and DIY whereas guarantee dealer would be closer to $1k for diagnosis, part and labour. Also - no booking in, no taking 40km to Indy, no not having car for a day. No going to get it.

You must be a very good customer of local Indy if he does that but it’s no good when you’re on the trail.

These cars are digital instruments with 20+ ECUs it’s just a tool but not a spanner. No different to spending same on a compressor and camping equipment.

[Homestar]

if this gap tool is so important to the functioning of this vehicle , why wasn't it built in to it?

More of the reason I don't or cant justify owning one.

the d2 was bad enough but my local indy let me do any scans free in their workshop....still do.

It’s like saying why don’t the OEM’s build in entire tool kits in their vehicles - they don’t want you repairing them yourself but taking it back to them so they can rape your wallet - a diagnostic tool is just another tool you can choose to own to reduce your independence on said dealer.

[Lukeis]

My understanding was it could be either of the following:

1- leaking airbag
2 - leaking or broken solenoid
3 - leaking hoses

So trying to be logical if the airbag isn’t leaking (as it doesn’t drop with the fuse removed) that rules out number 1

Wouldn’t that also rule out the other two as well?

it’s like the car THINKS it needs to drop the front, sends the signal to drop and the car behaves and keeps going every so often until it’s down to the bump stops.

what am I missing?

[josh.huber]

My understanding was it could be either of the following:

1- leaking airbag
2 - leaking or broken solenoid
3 - leaking hoses

So trying to be logical if the airbag isn’t leaking (as it doesn’t drop with the fuse removed) that rules out number 1

Wouldn’t that also rule out the other two as well?

it’s like the car THINKS it needs to drop the front, sends the signal to drop and the car behaves and keeps going every so often until it’s down to the bump stops.

what am I missing?

Nothing, your right. As you drive down the road the car is pumping the bags up. Once you stop and get out. Less weight. Car comes up. Sensor sees it's to high and let's it down on purpose.

It gets worse as the dampers inside the shock wear