Front suspension low

[XJ_Driver]

At the weekend I noticed my 2003 3.5SE is sitting conspicuously low at the front. It sits level, and the ride seems unaffected. I have no warning lights / messages showing, but the front fails to lift even after a decent drive. I don't know what's caused this, although I'm sure the shocking state of our local roads around here won't have helped.

If there's an air system fault I'm surprised there are no warnings flagged on the dash, and that the ride is still compliant. Any ideas what might have caused this?

Advice appreciated. Thank you.

[PaulGover]

If there are no warning messages, the suspension system thinks it's OK, but your eyes say not. So the most likely cause is the front ride hide sensor coming adrift, and thereby sending the wrong height information to the ECU. This is a pretty well-known problem; AFAIK the sensor that matters is in the LH front wheel arch, mounted on a bracket in front of the suspension gubbins, with a plastic and brass drop-link to a rubber bush over a pin on the suspension I'm describing the 2008 car, but I don't think this changed much)

The pin is retained by a nasty bit of bent tin, like one of those crimp-to-close pipe clips, really rather tacky for a £50,000 car, but then every penny counts. You'll probably find this clip has failed. You'll find several posts in this forum describing replacing it with plastic cable ties, and that's probably all that's needed. I've not need to do this myself, but I'd guess a plastic tie lives at least as long as a metal one. I guess once this fix in is, there's a possibility the ride height will be a few millimetres out, but that's unlikely to be significant.

[XJ_Driver]

Thanks Paul - I'll check out the LH ride sensor first to see if it's become dislocated. Measuring vertically from the front wheel centres to the highest point on the wheel arches is 330mm both sides, so the car's sitting level, but I believe approx. 5cm too low at the front currently.

[XJ_Driver]

So, this afternoon I removed the NSF wheel, finding the level sensor mounting bracket to be twisted, which in turn had dislocated the pushrod - almost certainly as the result of clouting a pothole. Carefully bent the bracket back into shape, reconnected the pushrod and, as soon as the car came off the jack, I could hear the compressor whir into life and at once the correct ride height was restored (385mm measured vertically from both front wheel centres to tops of the wheel arches). A quick road test to confirm all was well, and the job was a good un! Thanks again Paul