Just had a thought Ouch!

Has the relay for the pump been changed? Only I know it's supposed to be changed with the Wabco pump, and if it's got burnt contacts then it will not be giving the full beans to the pump. And it will run slow, and your tank will fill up slowly and your dash will BONG you and the screen of doom will read your walking! A poor earth to the pump will do the same thing.
If it is the ECU then your looking at around £150 S/H or £300 new, it is alot , but not as bad as it could be! But I'd look in to everything else first before going down that route, cos you know it'll need coding  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Take a read of my thread

Mine hasn't played up once since (touching wood quickly - lol)

http://www.fullfatrr.com/forum/topic18252.html

Hi,
I experience pretty much the same suspension fault symptoms on my 2006 L322, i.e. almost always ca. 30 secs after staring the car the dreaded “bing” and suspension fault warning. At this point the compressor shuts down. Haven’t had yet access to a hoist to check for minor air tube leaks but a few things are weird.

First, when requesting either an off-road or easy access movement before the “bing” the lifting or lowering works fine and the system does not send a compressor shut off signal.

Second, using the IIDTool, the system pressure quickly rises after starting and the reservoir valve opens to 100% from ~ 10bar (which would indicate an air tight reservoir) but once “binged” and the compressor shut off the (IIDTool “gallery”) pressure drops to atmosphere within ca. 5-10 secs.

Since the pressure sensor is mounted on the reservoir the IIDTool is showing the reservoir pressure and not the gallery (as I understand was used on earlier models) where is the pressure drop occuring the IIDTool is displaying?

Is an electrical problem more likely, since the EAS does work before cutting out? I.e. do vehicle movements wiggle a faulty harness? But this contradicts the pretty constant time interval before cutting out?

Also, it only used to throw failure code “pressure increase too slow” C1A20-64 and recently added “air supply component failure” C1131-92. And yes, I did service the compressor last year with new piston seal and dryer dessicant. Unless I mucked up, but seeing the pressure rise w/o fault after a complete air drain, I would assume that service went ok. Btw, how long does it take to fill a completely drained system back up to ca. 12bar?

Any ideas of enlightment out there?

Tom (2006, L322, TD6)

wow pal , this thread is 3 years old , suggest you open a new one to get a better response

Oz Tom, the compressor is failing. Changing heights requires less pressure than that used to replenish the reservoir, which only occurs once the target height has been reached. The 5 minute delay is typical of the pressure increase too slow fault.

Graeme...ta,

could that be a faulty valve within the air supply unit? But why is the so-called gallery pressure quickly decreasing after compressor cut out?
What do you mean by 5 min delay typical of compressor failure?

Cheers, Tomo

The compressor exhaust valve might not be sealing thus preventing proper pressure.

Is your pressure sensor on the reservoir side of the reservoir valve or on the compressor side? Later systems have it on the reservoir side - perhaps only from MY07 (uses the Terrain Response system from the Discos & RRS). The system exhausts the pressure side of the compressor when it stops, presumably so that the compressor isn't having to start against a high pressure next time.

Graeme,
won't have a chance to look it up today, but since the LR workshop manual released in 2002 already depicts the sensor directly screwed into the reservoir, I assumed that this is the case.
Tomo

juat a thought, have you checked your battery/alternator, 9/10 times, inactive suspension alarms related to low system voltage, after i changed my alternator, it cured a multitude of alarms on my 2004 td6, just sayin'.....

Yep, the devil is fully charged with relatively new (6 months) battery

hmm, although I did replace the piston ring, cleaned exhaust valve and replaced the desiccant I eventually replaced the compressor (for ca. USD 300 incl. shipping and taxes via the Chinese "Amazon") and bang - all fine, no error messages.

That happened to me.. rebuilt the compressor and there was very little improvement, in the end I just bit the bullit and brought a new one, instant cure!

The trouble is that when the compressor shows signs of needing a rebuild, it has already gone past the rebuildable stage... it needs to be done before the piston ring wears out, otherwise the cylinder becomes scored and the whole unit is useless  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Just adding another voice to the "air hose has chafed on the chassis" party. Car doesn't drop overnight, but had a hissing sound for around 30 seconds after switching off, and the occasional 'normal height only' bong message. 6mm blue hose has chafed on the chassis around 4 inches from where it comes out of the spare wheel well heading towards the valve block. Splice connector on order.