Disco 3 (LR3) Intermittent air suspension fault

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guineafowl21

Well-Known Member
Posts
3,349
Location
Inverness
07 Disco 3 HSE with 162,000 miles.
Intermittently gives suspension fault warning when first started up as I drive away. Always goes away if the key is cycled.

Codes (read with iCarsoft i930 V2):

C1A36 Exhaust valve
U0416 Invalid data from vehicle dynamics module
U0100 Lost comm with ECM/PCM
C1A20 Pressure increases too slowly when filling reservoir

Also got a compressor temp too high when I was farting around raising and lowering.

This morning the vehicle was sat with the RR much higher than the others. Height sensors reported the other wheels at about 50mm, but the RR at 67.

Resting gallery pressure 200 kPa, when comp running 1500.

I’ve left it raised up and on level concrete to see what it does overnight. Any suggestions welcome. Faulty RR sensor? Leaky FL strut?
 
I would guess weak compressor, the pressure building to slow and the compressor overheat would be the clues to me.
If you look on the D3 forum at the wiki section which is at the top of the page and click on it there is a whole section of common faults and their fixes.
 
Thanks Lynall.

None of the corners dropped at all overnight.

Pulled out the compressor, which is an AMK made in 2013. Stripped it down and it looked fine inside, including the dryer granules.

Next step was the intake filter, but I couldn’t find it. Any idea where it is? Haynes manual says it’s in the left-hand boot compartment, but it isn’t.
 
guineafowl21 said:
Thanks Lynall.

None of the corners dropped at all overnight.

Pulled out the compressor, which is an AMK made in 2013. Stripped it down and it looked fine inside, including the dryer granules.

Next step was the intake filter, but I couldn’t find it. Any idea where it is? Haynes manual says it’s in the left-hand boot compartment, but it isn’t.
Click to expand...


Its under the floor inside edge of nearside chassis rail I think?

Just had a problem with wifes Audi compressor and theres a guy selling piston rings on ebay and he reckons these are the main part that goes weak as they wear, think called airbagandy or airpipingandy?

Did you check the air tank for leaks with soapy water? from memory one end or the other rots and gets pin holes.

Iirc the height sensors figures are not that important the level is more important and you can adjust the figures to get it level and even when level the figuts the ecu sees cna be all over the place.

Gary is good at this I will pm him for you.
 
Found the air filter - out of sight almost right behind the left rear light. Removed the light and vent behind, then I could access the back of the plastic clip to pop the filter free. Didn’t seem too bad but giving it a clean anyway.

Sprayed the air tank with soapy water - nothing.

Compressor cuts out at about 1700 kPa “gallery pressure” (air tank?) but then starts to drop off immediately. Over about ten minutes it dropped from 1700 to 288. Is this normal?
 
guineafowl21 said:
Found the air filter - out of sight almost right behind the left rear light. Removed the light and vent behind, then I could access the back of the plastic clip to pop the filter free. Didn’t seem too bad but giving it a clean anyway.

Sprayed the air tank with soapy water - nothing.

Compressor cuts out at about 1700 kPa “gallery pressure” (air tank?) but then starts to drop off immediately. Over about ten minutes it dropped from 1700 to 288. Is this normal?
Click to expand...

if compressor is builiding up to 1700 in a short time then you can say thats good.
I think the gallery pressure should hold at whatever the pressure is when engine switched off, but the system never actually goes to sleep so if you have a leak it will try and correct it until it runs out of air.

If you go back to the silencer and listen (again this is from memory) the air is sucked in via the filter and also vents via the filter, this is to dry the dessicant in the compressor, so if its venting you should hear it, or failing that stick a latex glove over the pipe.

If the compressor is an AMK which is the better one, I think there was some sort of pipe mod involved.

Forgot to say there are three valve blocks controlling the air suspension and you can get an o ring kit off of ebay for 20 quid, not sure if the 20 quid does one valve block or all of them?
 
Last edited:
lynall said:
O ring kit, looks like it does all three blocks, https://www.ebay.co.uk/itm/Range-Rover-Sport-Air-Suspension-Valve-Blocks-Replacement-o-ring-repair-kit-set/283260092481?fits=Car+Make:Land+Rover&hash=item41f39e0041:g:bHgAAOSwJMhXESAF
Click to expand...
I’ll look into that, thanks.

I’ve buttoned it all up again, to see how it performs now.

The wife generally drives it, and she’s just mentioned that while a fault message was displayed, the car felt unstable at speed, sort of wallowing. I wonder if a front or rear valve block has a sticky valve, letting air pass across axles.?
 
guineafowl21 said:
I’ll look into that, thanks.

I’ve buttoned it all up again, to see how it performs now.

The wife generally drives it, and she’s just mentioned that while a fault message was displayed, the car felt unstable at speed, sort of wallowing. I wonder if a front or rear valve block has a sticky valve, letting air pass across axles.?
Click to expand...

Tyres make a massive difference to handling, even half worn tyres can make the air ride land rovers feel strange, tired dampers on the older cars dont help either.
 
lynall said:
Tyres make a massive difference to handling, even half worn tyres can make the air ride land rovers feel strange, tired dampers on the older cars dont help either.
Click to expand...
Tyres are reasonable, but I’ve topped up all the pressures anyway. I’ll see how the thing goes for now, as I’m reluctant to jump in with a new compressor.
 
Hmmm, didn’t think of that.

Well, I’ve done my usual approach to annoying intermittent faults - have a tootle around for something obvious, then hand the car back to the wife to see if it gets worse. If it’s battery or compressor it should get worse.
 
guineafowl21 said:
Hmmm, didn’t think of that.

Well, I’ve done my usual approach to annoying intermittent faults - have a tootle around for something obvious, then hand the car back to the wife to see if it gets worse. If it’s battery or compressor it should get worse.
Click to expand...

If its bettery the Yuasa 019 is pretty good, halfords with a trade card is worth doing, best thing with halfords is get an issue and you can physically take it back for them to check, none of this courier rubbish.
 
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