Hello everyone,

I've been receiving random "Air Suspension Fault" messages on the dash for about three weeks. There didn’t seem to be any rhyme nor reason to the timing. Since I had successfully rebuilt the compressor 10 years ago and found it to be a simple procedure, I decided to do it again (along with throwing some fresh Akebono pads on the front wheels while my hands were refreshingly dirty).

Naturally, that didn't resolve the issue.

By accident, I discovered that the car was still running on its original battery—making it over 20 years old (see photo below)! I immediately replaced it with an Interstate H8 AGM from Costco. At $180 it was a bargain compared to other sources for the same battery.

The suspension error messages went away for a bit, but yesterday the fault came back on after about 10 minutes of driving. Today, it popped on instantly right after hitting a sharp bump (railroad tracks).

Mechanically, the suspension seems perfectly fine. The car pumps up beautifully and doesn't sag. After sitting for 15 hours, the ride heights (measured from the floor to the fender lip) are holding steady at:

• Front Driver / Passenger: 28 ¾”
  
• Rear Driver / Passenger: 27 ¾”
  

Before I rebuilt the compressor, I scanned it and somehow deduced the pump was the culprit, though I can't recall the exact code. Given that the car holds its height perfectly but throws a dashboard fault randomly, I'm starting to suspect a glitching height sensor or a wiring issue rather than a physical air leak.

Before I dive back into searching the threads, I thought I’d ask this august and highly esteemed body of refined scholars, gentlemen and fellow grease monkeys for suggestions. Any insights would be greatly appreciated!

Carpe diem,

Steve S.

 

Just in passing, AGM batteries are not preferred for the X350, they don't like the high voltage loads of the X350.
I concur with your view of a maybe not firmly attached or failing sensor or wiring issue: to be checked.