Strange Issue. My air suspension has been going flat overnight and now won't raise up when the car is started in the morning like it used to. Due to current circumstances, I cannot afford to get the car fixed (maybe in a month or two). However, I discovered that if I drive the car (slowly) a bit around the neighborhood, the car raises up. So, sitting still in the driveway, the car won't raise. Driving, the car raises. Any idea why that would be?

 

Any suspension codes? Those can only be read by JLR code reader like icarsoft

 

Can you hear the compressor shortly after startup? (I have to stand in front of the bumper). Maybe the compressor is worn out though working slowly, it would cut out after a few minutes whether or not the car is raised.

The book (in the stickys) confusingly says the compressor will "normally" only run above 25mph or cut out below 18mph. "Normal" ha!, mine runs when engine is started IF it's gone down.

The compressor is prone to overheat (but I see you're in Virginia in May), anyway it may be they say that for airflow. Other things that can inhibit the compressor are stated as voltage and ambient temp (i.e. are those sensors OK?)(and is the car charging?)

Assuming the reservoir or it's valve is not leaking but the struts are, the car should be able to do ONE pump-up on unlock i.e. without even activating the compressor.

The only cost I can see of suspension going down overnight, is that more use is made of the compressor and that's certainly a wear item.
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X350 owners will understand it's a marital issue as much as air suspension. I know I have ONE pump-up on unlock. So I'm not very impressed when she asks me to unlock the car just because she left her purse in there... (but if it's to check something for you guys, that's understandable)

 

Yes, I can hear the compressor shortly after the car is started.

Frankly, I've had air-suspension issues for some time (car going flat), but have not been able to afford to get it fixed (sadly). But the car has always just raised up after starting it in just a few minutes without issue and then driven normally. Now, it doesn't want to raise up unless driven. But, as stated, I do hear the air compressor, as I did previously, shortly after starting the car.

A second thing - the car is completely flat the next day. However, I don't always get the "car too low" error message (or whichever the exact message it is) with the red light. So, I'm wondering if a sensor is busted?

 

Compressor refurbish kit by bagpipingandy is cheap and might work.
I suggest you try with soapy water spray bottle in engine bay top of the struts .
In the boot after taking out your carpet your airline connections and top of the struts as well as the connections on the tank and valve block
your comp should deliver 14 bars of air that goes directely to the tank in the back ' from there on in 4mm or 6mm black hoses towards the struts in the back and in the front.

While your car is off , every half an hour Cats behind your back seat regulates the height an even the level of the car until, well there is not enough air anymore in the tank.
so your struts are dropping until there end of travel bag inside the strut with I believe 4bar so it does not fall against the floor
I installed a new comp. a year ago and by turning the engine on the car rose again to normal level in one shot.
air struts on those cars seem to dislike the heat.
it sounds like yours are losing pressure either over the struts all round or... the black hoses ...but the compressor is more likely the culprit , just worn out and could be refurbished or either exchanged .
oem is Wabco .i got my new one for 320 €, a refurb.kit would be like 50€.

As I installed the new one and ran it the first time the hose got blown out (deteriorated sealing nut and olive) the car went down immediately. Those tiny connections
are very sensitive as well as the nylon hose wich needs a clean cut and no scratshes.

 

 

When you start to drive slowly the comp. Starts at about 25km/h 15mph to deliver air so the car can rise
when you have vehicle to low written text and the fender just goes over the tire but not over the rim/wheel you can do that but slowly , not on a ramp, not over bumps

 

"I don't always get the "car too low" error message"
I've never seen that message. I've currently gone down from 3 fingers to 1 finger which it's been parked at for a week. Sometimes 0 fingers with no message.

Since your air suspension seems otherwise operational, I'd be thinking a compressor rebuild like he said. How much leaking you can put up with is a separate issue.

Someone suggested "don't disconnect the battery" while your car goes down. Apparently height sensor calibration could be lost.