P38 Air suspension

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R

radford19

Member
Posts
41
Location
East Sussex
OK, I knew it had an issue but it normally self corrects. If I do a few miles all is well. If I only do short trips for a few days level drops but usually comes back fairly quickly. All the lights go out. Today it sunk to the Access Mode. It has done this before and come back up. The Standard height light was flashing showing that it was trying to rise. But the main warning light was out and no message on the message centre So, I took it for a drive. After about five miles all the lights came on, the warning light and the message centre. However, it had regained the ride height and was performing as normal. I sought out some stretches of really bad road and it was fine. All the lights are still on. Now, a long shot. I have noticed in the handbook that the tailgate can have something to do with things. Yesterday, I removed the trim to clean the lower edge of the tailgate and the body behind it. I did stuff large amounts of cloths in the holes around the electrics as a precaution and blew around with an air line afterwards but I don't think any water got in there. Coincidence? Is anybody able to give me some clues?
 
Just EAS fault, no door open at all. EAS fault comes on for a short period then goes out. Is it possible I have upset something in the tailgate then?
 
radford19 said:
Just EAS fault, no door open at all. EAS fault comes on for a short period then goes out. Is it possible I have upset something in the tailgate then?
Click to expand...

As said the only influence the tailgate can have on EAS is if it's open and the EAS is then disabled. It cannot rise or fall. If that was open you would be getting tailgate open message. You need diag on it to pinpoint the fault. Off hand maybe a weak compressor. If you go to the tech archive and look at my EAS post, there are instructions for how to check this and other aspects of operation. But you need diag guessing is not an option.
 
Thanks for your help. I do understand the system but not as on a Range Rover. I have had Mercedes and Rolls Royce with hydraulics but they have been largely mecahnical. I do aim to go to a local Land Rover/Range Rover specialist to ask him to do a diagnostic for me.

I have just checked, no tailgate warning, I opened the tailgate, got the warning, closed it, warning goes. Did that several times.

Looking through the history I see that the compressor had new seals and cylinder fitted 20th December 2012.

Ordinarily the light goes out quite quickly and this is a sudden fault? Thanks again for your help. I will get it diagnosed hopefully tomorrow.
 
wammers said:
As said the only influence the tailgate can have on EAS is if it's open and the EAS is then disabled. It cannot rise or fall. If that was open you would be getting tailgate open message. You need diag on it to pinpoint the fault. Off hand maybe a weak compressor. If you go to the tech archive and look at my EAS post, there are instructions for how to check this and other aspects of operation. But you need diag guessing is not an option.
Click to expand...
Thanks again for your help. Does my confidence a lot of good on something that I am still learning about and don't fully understand .... yet. I have had the people do a diag check and you were right, a weak compressor. They were surprised that with a full house of lights the ride height was right and everything was working as it should. He reset the lights and said to take it for a drive and ........ so far ............ They didn't suggest any urgency on the compressor, so I will keep it in mind to sort out.
 
radford19 said:
Thanks again for your help. Does my confidence a lot of good on something that I am still learning about and don't fully understand .... yet. I have had the people do a diag check and you were right, a weak compressor. They were surprised that with a full house of lights the ride height was right and everything was working as it should. He reset the lights and said to take it for a drive and ........ so far ............ They didn't suggest any urgency on the compressor, so I will keep it in mind to sort out.
Click to expand...
Diagnostics do not give an indication of the state of the compressor, nor can the lights be reset as such, they will resume normal operation when the faults are cleared. All lights on indicates a fault and normally the EAS goes up to the high position. It would be useful to know exactly what faults were logged.
 
wammers said:
As said the only influence the tailgate can have on EAS is if it's open and the EAS is then disabled. It cannot rise or fall. If that was open you would be getting tailgate open message. You need diag on it to pinpoint the fault. Off hand maybe a weak compressor. If you go to the tech archive and look at my EAS post, there are instructions for how to check this and other aspects of operation. But you need diag guessing is not an option.
Click to expand...
Hi, Sorry to be a pain. Just a little update. The other day it was reluctant for the light to show that it had risen to the right ride height. I popped the cover off the compressor and poked and prodded the relays, connections etc. Then I 'twisted' what I think is the inlet air filter and the compressor kicked in, turned it a bit and it kicked out. Turned it back and it kicked in again and it has been fine evre since?? I really cannot understand why that would help. Is it a replaceable part? Does it get blocked and can be cleaned? The manual doesn't appear to tell me. Any advice much appreciated. Thanks
 
radford19 said:
Hi, Sorry to be a pain. Just a little update. The other day it was reluctant for the light to show that it had risen to the right ride height. I popped the cover off the compressor and poked and prodded the relays, connections etc. Then I 'twisted' what I think is the inlet air filter and the compressor kicked in, turned it a bit and it kicked out. Turned it back and it kicked in again and it has been fine evre since?? I really cannot understand why that would help. Is it a replaceable part? Does it get blocked and can be cleaned? The manual doesn't appear to tell me. Any advice much appreciated. Thanks
Click to expand...
The inlet air filter can certainly be replaced, it can also be cleaned. I can see no reason why turning the filter should cause the pump to kick in/out, I have to assume it's coincidence. The connectors are a known trouble point, the contacts may need a clean and possibly tightening.
If the pump is starting and stopping often, it may be feeding a leak.
 
radford19 said:
Then I 'twisted' what I think is the inlet air filter
Click to expand...

A picture is worth a thousand words, so I'm told. Phone out, snap a picture, upload and we'll see.

Cannot see how the filter would make much difference but you never know. As Datatek says, maybe you're disturbing something else.

Have you been through Wammer's checks in the Technical section? Particularly the bit about checking compressor output? If it does have a leak it will kill your compressor. They can take a duty cycle of 30% but not much more.
 
If your compressor is on the the way out then I'd reduce it's need to kick in as much as possible. IMV the stock EAS control makes rather to much of a meal of ride height adjustment, and constantly wants to mess with that throughout a journey, and when the vehicle is parked (every six hours). This will cause unnecessary wear, particularly as others have said if you have a leak in the system somewhere.

As long as the leak is a slow one and will take several days to reduce the ride height it is a simple matter to prevent the compressor from running until it really needs to. The way I have done it in the past is to remove the 10A EAS fuse in the fusebox under the bonnet. The way I do it now is quite elegant because it utilises the inhibit switch on the dash, and requires soldering just two wires. I have (cough) posted on this in another forum - not sure about local etiquette here so I won't link that but a quick search will probably bring the detail up, if you're interested.

The result for me is that I can easily relevel the vehicle at the start of the day/week or whatever and it will simply stay at that level without the compressor operating until all the air leaks out and/or I wish to adjust it again. Practically this means that with a slow leak and when the vehicle has dropped from normal ride height to low say I would push the new 're-level' switch for a minute or so every 3 or 4 days; that's only time the compressor needs to operate.

Of course this means the suspension can't adjust itself on the move. This is not important to me - and in fact is what I prefer - but it may matter to you...
 
private_user said:
If your compressor is on the the way out then I'd reduce it's need to kick in as much as possible. IMV the stock EAS control makes rather to much of a meal of ride height adjustment, and constantly wants to mess with that throughout a journey, and when the vehicle is parked (every six hours). This will cause unnecessary wear, particularly as others have said if you have a leak in the system somewhere.

As long as the leak is a slow one and will take several days to reduce the ride height it is a simple matter to prevent the compressor from running until it really needs to. The way I have done it in the past is to remove the 10A EAS fuse in the fusebox under the bonnet. The way I do it now is quite elegant because it utilises the inhibit switch on the dash, and requires soldering just two wires. I have (cough) posted on this in another forum - not sure about local etiquette here so I won't link that but a quick search will probably bring the detail up, if you're interested.

The result for me is that I can easily relevel the vehicle at the start of the day/week or whatever and it will simply stay at that level without the compressor operating until all the air leaks out and/or I wish to adjust it again. Practically this means that with a slow leak and when the vehicle has dropped from normal ride height to low say I would push the new 're-level' switch for a minute or so every 3 or 4 days; that's only time the compressor needs to operate.

Of course this means the suspension can't adjust itself on the move. This is not important to me - and in fact is what I prefer - but it may matter to you...
Click to expand...

The compressor does not run for six hourly parked up levelling. It only levels downwards. Whilst driving the only height changes that are made are the drop to motorway over 50 MPH and the return to standard under 35 MPH. These can be eradicated by use of the inhibit switch to lock at either height. There is no need for any other switch. The suspension does not constantly adjust height, other than previously mentioned whilst the car is being driven, unless there is a leak to be catered for, in which case air will be needed to service that and the compressor runs to maintain pressure in the tank..
 
Last edited:
wammers said:
The compressor does not run for six hourly parked up levelling. It only levels downwards. Whilst driving the only height changes that are made are the drop to motorway over 50 MPH and the return to standard under 35 MPH. These can be eradicated by use of the inhibit switch to lock at either height. There is no need for any other switch. The suspension does not constantly adjust height, other than previously mentioned whilst the car is being driven, unless there is a leak to be catered for, in which case air will be needed to service that and the compressor runs to maintain pressure in the tank..
Click to expand...

I'm amused - because of course "you are quite right again dear Wammers"! However I did leave some detail out of my post in the interests of not making it too complex:

Anything that reduces the ride height (reduction at 30/50 mph, or the dreaded re-level per 6hr) will mean that air needs to be used to get the vehicle back to ride height. Coupled with the re-level that often occurs at stop (at least it does on mine @ traffic lights for instance) this means the compressor will need to operate significantly more than it really needs to (IMO).

The 'standard' inhibit switch operation will not stop the 6-hr adjustment as I recall, nor will it prevent compressor operation per se. A minor alteration to its operation does both of these things.
 
private_user said:
If your compressor is on the the way out then I'd reduce it's need to kick in as much as possible. IMV the stock EAS control makes rather to much of a meal of ride height adjustment, and constantly wants to mess with that throughout a journey, and when the vehicle is parked (every six hours). This will cause unnecessary wear, particularly as others have said if you have a leak in the system somewhere.

As long as the leak is a slow one and will take several days to reduce the ride height it is a simple matter to prevent the compressor from running until it really needs to. The way I have done it in the past is to remove the 10A EAS fuse in the fusebox under the bonnet. The way I do it now is quite elegant because it utilises the inhibit switch on the dash, and requires soldering just two wires. I have (cough) posted on this in another forum - not sure about local etiquette here so I won't link that but a quick search will probably bring the detail up, if you're interested.

The result for me is that I can easily relevel the vehicle at the start of the day/week or whatever and it will simply stay at that level without the compressor operating until all the air leaks out and/or I wish to adjust it again. Practically this means that with a slow leak and when the vehicle has dropped from normal ride height to low say I would push the new 're-level' switch for a minute or so every 3 or 4 days; that's only time the compressor needs to operate.

Of course this means the suspension can't adjust itself on the move. This is not important to me - and in fact is what I prefer - but it may matter to you...
Click to expand...
Potentially dangerous nonsense.
 
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