My 2008 TDV8 has flashed up the “normal height only” message, and my mechanic thinks it’s the compressor or “compressor system”. Would I be right in thinking that this could be any of the following:

Compressor?
Air bags?
Height sensors?
Fuses?

Assuming it’s not fuses, what would the likely cost of parts and labour be for a new compressor, new airbags and new ride height sensors? I’m thinking I could get it all done at once for “future proofing” rather than have them fiddle around for hours looking for which component is faulty.

Any way to tell which compressor I have without digging out the part itself?

Any decent suppliers for the above parts?

All advice welcomed.

Get the code reader on it first. Then go from there.

Rusk - get your battery checked as well. Mine was dying slowly and started to switch of special programmes including adjusting heights. Previously owned 1999 Disco 2 TD5
Disco 3 HSE TDV6 2007
Gone 2007 TDV8 RRS1 in Buckingham Blue.

How do know if the knocking at the front has been sorted?

You can hear the knocking at the rear better

Also check that all your tail light lamps are working - a blown lamp at the back can throw up all sorts of warnings on the dash 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

Assuming fuses checked, the compressor and height sensors are the most likely cause. The sensors being the most likely of those two.

The airbags are pretty robust and very rarely cause a failure - they are much more robust than the old days of the P38 etc. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

A tip is to check the 4*4 screen, it will show a small flashing red box if there is an issue with a particular corner. helps with fault finding if you don't have a code reader..

Thank you for the help so far...

The only red flashing dot I can get on the 4x4 info screen is the front right wheel, if I lower the suspension to “access height” when I’ve just started the car up and the suspension fault warning hasn’t kicked in yet.

That same wheel was the one that had a slow puncture that I had to keep topping up with air whilst I waited for my new wheels and tyres to arrive - might that be related?

I wondered if that air bag was leaking but is it possible the constant topping up has scuppered the sensor on that wheel???

Check the tyre make and size against the others.

Some manufacturers are actually quite different in size. This cause the ecu to get messed up as it thinks it’s continually going round corners lol and is free to do!

Identical Pirelli Scorpians on all wheels... previously identical Nexxens on all wheels BUT the offending wheel was the one that had a slow puncture.

Ok I would check tyre pressures, then measure the height of the suspension using a tape measure from the underside of the wheel arch to the top of the center hub cap. (For calibration purposes it’s measured to the center of the cap)
In normal operation the ecu allows up to a 10mm difference before adjusting, anything greater than 10 mm COULD indicate its out of calibration. I’m out now and can’t remember the measurement for the front. If you google gap IID tool the instructions book contains the required measurements.

Take the measurements once you have moved it approx 5 meters and are on level ground with the engine running.

The next thing to do would be a hard reset of the car. Disconect the battery for ten minutes. Remove both pos and meg terminals. Before reconnecting short the two leads together, this discharges any remaining current. You will need to reset the radio etc but this clears all faults from the ecu memory. If it comes back then you do have an issue. If it doesn’t then mines pint 🍺

Without a code reader there is no more you can do. I fully recommend either having a good friend with one or for approx £400 the Gap IID tool is the one to get.

Happy to do a hard reset... but I don’t seem to have a radio code...

Will a hard reset cause any other issues?

There is no radio code, just need to reset date, time, and radio stations memory.

No other issues..

And touching the battery cables together won’t up the electrics!?

No it won't  2016 Black SDV8 Autobiography
2013 Grey Black Edition SDV6 (lasted a while but gone now)
2005 Grey Supercharged Sport (gone but never forgotten)

Did this today - exactly as above, but it doesn’t shift the fault - so looks like a new compressor... BUT, can anyone give me an idea of the labour time on replacing the ride height sensors?

And, is recalibration after fitting likely to be something only a main dealer or specialist can do?