The 4.8is has 4 air bags, the older 4.6 has just the rear like your car. Commonly, when the air bags start leaking, the compressor has to work a lot harder and fries it out. For some reason, the control module goes bad after that. At least that's what happens in the X5s. I'm sure it's the same technology. You can thank Range Rover for the air suspension system...
If the bags look original, I'd replace them as PM. They're cheap enough and when the bags get worn, they start weeping so there won't be an obvious hole.
A sign that the bags are leaking is when you come out in the morning and one side or the whole rear will be sagging. The system is designed to keep the car level even when its turned off but eventually the system will time out to save battery life. Arnott sells the compressors for half the price of OEM and there is a guy on eBay that sells a compressor rebuild kit if you ever have to go down that road...
Dinan CAI &Throttle body, ESS Tuning TS2, Bimmerbrakes gen3 headers, UUC SSK & DSSR. Achilles oil pump, VAC oil pan baffle
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