Repair price depends on whats gone wrong, I'm sure someone will arrive soon to give you a run down on that....what year / model do you have? The airbags have a lifespan of around 8-10 years max, if you're lucky, so these may need changing. Alternatively, the compressor may need attention or the height sensors. Either way, you will need to plug in to Faultmate or Rovercom or the main stealers computer at about £70 a pop so the fault can be isolated and reset once repaired.......EAS faults can be really expensive and some people rip out the kit and go for springs, but part of the pleasure of a P38 is the suspension, in my opinion, so I would never do that.....
Hope you get it sorted, can't think of a worse ride than a Range Rover on its bump stops!!! I had an aftermarket kit installed which allows you to inflate the airbags at any garage air pump after removing the fuse under the passenger seat of course, then the ride becomes more tolerable until it can be repaired!