My 2003 TD6 has given this message a couple of times and not sure why. I use the car daily for work and one visit I do is on a short rough track. When I leave the track onto the bitumen once I hit about 60kph I randomly get a Bong with the OFF Road slow 50 kph message. No Dramas, everything works OK, once the bong repeated itself after a minute but other times just once then its gone and only does it again until I leave the same track. It does not do it every time. I am wondering if the suspension extends a bit on the track and is slow to level back down. Is this a known problem, is there a known cause. Is it normal? I can find nothing searching this forum or elsewhere.
The only thing I have found that could possibly be related is the exhaust on the compressor being blocked, is that likely? 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Not sure if this is correct or applicable but, on mine (touch screen), you can set the nav for on road or off road. If yours is set for off road it may be recognising leaving the road and acting accordingly.

 John
2008 Stornoway Grey 3.6 Tdv8 Vogue
2005 TD6 Java Black Vogue - Written off!!
GAP iiD BT
2003 Discovery TD5 Auto, Nanocom Evolution - gone to a new home!
MasseyFerguson 152 - No electronics!! - Sold

Interesting , so you are not putting the car into off road height right ?
For some reason it thinks it is . Do all your different heights work ok ? like access , normal and off road ?
On you model unlike later once you can adjust all heights individually , maybe you need recalibrating . 2008 MY Supercharged
Rimini Red / Jet
four zone climate
remote park heater
and no ugly kid windows.
magnus satis quod turpis satis

Axle,, I am not putting the car into off road height or low range. All the suspension settings work perfectly as the low / high selector. The car just seems to think its in High / off road mode when I hit the tarmac. The suspension height lamp is in normal mode (centre). The track I use is only 100mtrs long and not in any way hard, I would drive it in a ford fiesta if it was not mine. My thoughts are with the bit of flexing the suspension raises a bit then is slow to lower back. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Mine does this occasionally as well, I think its just if a wheel moves slightly more than the normal ride height tolerances it will trigger the height sensor while its correcting its height - such as a sharp road camber angle change or a transition from a deep rut/channel - as it corrects itself straight away I don't tend to worry about it and only seems to happens at low speed. Current Fleet:-
2018 Discovery 5 3.0 HSE
2021 Ford Ranger Wildtrack
2019 Ford Mustang Bullitt 5.0 V8
1993 Defender 90 200TDI Pickup

Gone - not forgotten
2016 L405 4.4 SDV8 Vogue SE
2012 L322 4.4 Westminster
2004 L322 4.4 V8 Autobiography LE
2000 P38 RR 4.0 HSE (ex Clarkson test car)

I expect it's just the suspension has been levelling it's self on the rough track, as the suspension has had a lot of travel in it then it naturally raises the car over all, and it takes a little while for it to settle back down again. Might be better next time to try putting it in off road height when you're on the track and switching back to normal height manually when you leave it. I would think that way you'd be helping out the suspension computer rather than letting it guess.

I will try raising the suspension when next on the track. I will also have a look at the Exhaust on the compressor when I get 1/2 hr. Thanks for the input. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

Mine does exactly the same all the time when off roading, it will be in normal height and bong the message... I went through all the settings and live data streams and have concluded it is as has been guessed above... the poor little thing thinks the car is a bit high and lets you know...

I just ignore it now, had no other problems or faults and it doesn't hang about long anyway, also stores no faults....

Just another FF idiosyncrasy......  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I suppose in effect what it does is automatically detects it's on rough ground and raises the suspension, in the same way that it lowers it on a smooth motorway at speed. (in a roundabout sort of way)

Hydractive Citroen's do this, they raise automatically and tell you to slow down on rough ground, then lower again automatically when the surface smooths out.

The early ones certainly don't raise the level automatically and they have no way of "knowing" if they are offroad or not, the later ones do and can adapt to different surfaces...

The early ones will go into a fake live axle setup and lower one side when the other side raises but this only happens when you put it in off road height, in normal height it doesn't do it....

Pretty sure it's just the fact that the system is pretty basic and when it self levels, which it is doing all the time anyway, if you are traveling in a straight line, it ends up leveling to a slightly higher level, gets confused with it's little self and bongs..... Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Sorry I didn't really explain myself well. What I meant was that while it doesn't do it by design. Lots of axle articulation has the side effect of raising the average level of the suspension. So it's like a crude way of the suspension self raising on rough surfaces. When the road smooths off it realises it's too high so settles down again.

Page 60.10 of the WSM under cross link valve:
"The air suspension ECU senses that the vehicle is off-road by comparing rapid changes in signals from the height
sensors. The operation of the cross-link valves is fully automatic, requiring no driver intervention.
The cross link valves are only operated at vehicle speeds of 12.5 mph (20 km/h) and below. At vehicle speeds above
12.5 mph (20 km/h), the cross link valves remain closed."

In other words if the ECU senses rapid changes in the height sensors it assumes it's off road and therefore the warning will pop up. It's not trying to raise the car into off road mode, it's just sensing rapid changes.
Below 12.5mph the cross link valve opens so left and right air bags are connected. If one wheel drops into a dip and therefore extends the air spring, the other side will decrease in height as the air moves across to fill the extended spring. It keeps the body as level as it can improving the ride, it only does this under 12.5mph (20km/h).

It senses you're off-road, wants you to slow down so it can give you a better a ride and not hammer the suspension.
Ignore it

What it doesn't say in the manual is that the cross link valves only go live when you are in raised off road height... at least, mine don't...!!!! Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I do alot of off road driving and never come across this, the cross link should come on in standard height too.

I completed my daily off road adventure today but this time put in high mode. When on the tarmac again 100mtrs later I set it to std height and continued on with no messages or bongs.. As others seem to have the same warnings I will just ignore it in the future. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone