air suspension fault - possible valve block

[scottiev]

Hi, I've a Minor issue (hopefully) with my Air Suspension and I was hoping someone could help?

I recently being getting the bong and orange light after start-up ( 5mins or a few km's).

I put it on the test book and these were the comments:

RLM Faults:

U6416-86 Invalid data received from vehicle dynamics control module - signal invalid
C1A20-64 : Pressure increases too slow when filling reservoir - Signal plausibility failure.
C112F-72: Air Spring valve. - Actuator is stuck open.
C1130-66: Air Spring Air Supply. - Signal has too many transitions/events.

I haven't taken the car apart yet, check any valve blocks, etc.

I did and electrical test and isolated the system over 24hrs to monitor the air bags for leaks. The outcome was a 10mm drop in the front and similar increase in the back, odd?

Also I should mention the operation when I start the disco.

The car levels itself, pumps up the front, adjust etc..... the compressor runs, slight rough, after

The compress runs for a while then I hear a knock like a valve closing at the compressor housing, light dims and bong, normal height only.

Turn the engine on and off and she's alright, until I touch the height controller!

Any advice?

[Marmoset]

What year is is Scottie? If it's an early one like min (2005) then the block connectors in the front LH wheel arch and associated wiring can give some problems.

I'd more than likely guess that it's a compressor issue because of the filling too slowly error and you say it runs rough, but there may be other problems on top of that.

If the air valve actuator is stuck open it makes me think of a wiring problem to that. Which actuator is it referring to?

[Graeme]

I'd go with a front valve block fault, either one side stuck open or split where the airline is connected. The compressor might just be struggling to keep working with a leaking valve block. A broken wire would show as an open circuit or solenoid failure and would not cause air to leak from the airspring.

Whilst the front and rear valve blocks can be swapped in order to see if a problem transfers to the other end of the vehicle, the vehicle will rise much more quickly at the rear and even more slowly at the front than it nomally does and probably not worth the work in swapping anyway.

[scottiev]

I think you might be right Graeme, the diagnosis doesn't mention any compressor problems. The compress runs longer than I think it should (minutes rather than 30sec to pressurise), the compressor tappers off like its reaching pressure then stops with a solenoid like sound.

I'll start with the valve block, not a small job. How do I remove the voss fittings without needing new ones, anyone know?

Marmoset, the age is Jan 2007, compressor changed in 2010 @ 70k, now 100k. oh and it Just says Air Spring Valve, so any I suppose.

more likely the valves I think.

I do a lot of sand driving in WA, maybe some got into the system, otherwise it could be the air dryer letting crap in and sticking in the valves.

For the from to drop and rear to raise (system disabled over night), could it be a number of valves leaking?

System overhaul.

[Graeme]

The rear may only be rising due to weight transfer to the front as the front lowers.

The hose fittings unscrew from the valve blocks - be careful not to cross-thread when refitting.

The air pickup filter is inside the vehicle behind the left tail-light so sand contamination is unlikely to be the cause.

Have you cleared the faults then had another look to see which ones come back?

[scottiev]

Hi Graeme, I haven't checked the fault again, its $77 a pop for the test book at third party in cannington. I am assuming the same issues.

funny thing is, once the orange light comes on and stop and restart it's fine, unil either a change the height or leave the car for several hours (over night or while at work).

[Graeme]

The warning light not re-appearing after a restart suggests the cause of that particular fault is the reservoir pressure rising too slowly on the initial start but give it another go after the restart and either the pressure is near enough to not warrant restarting the compressor or the reservoir pressure is reached within an acceptable time. That still doesn't guarantee that the compressor is at fault if its had to work overtime to cater for a leak somewhere.

Its time to get yourself a suitable fault code reader rather than keep guessing the faults or paying to have them read.

[ctgiles84]

To find out if its valve block pull fuses in she'd over night. If the car goes down only front or rear then the valve block is in need of replacement or rebuild. Does the car go down overnight?

[Bens]

hey guys,

I have a 2006 LR3 and the rear right hand side is sagging over night but returning to the standard height once i start the car in the morning.

This morning I sprayed soapy water around the air bag for that side and couldnt see any onbvious signs of a leak in the bag. One thing that is odd is that the compressor releases short air bursts when i stop the engine. could this be a problem with the valve? i couldnt see a great deal under there so i wasnt sure where to look for the valve. any assistance is greatly appreciated. i managed to avoid a visit to the mechanic with the last issue (break switch replacment) so hoping i can do the same again.

cheers. Ben