Thread: Help needed: p38 Stuck on Access

Hi AlfaMale, a few questions for you to try and work out what's going on.

Do you get any faults appearing on the nanocom or message centre?
Have you rebuilt the valve block at any stage?

At a guess it could be a fault in the valve block causing the vehicle to keep rising to wade height, could also be a fault in the driver pack .
If it was me I'd probably start with a valve block rebuild to at least rule that out, somehow air pressure is going into the air springs.

Are you allowing enough time (leaving a door open) for air pressure to build up enough before trying to raise the vehicle?
How long since the compressor was rebuilt?
Could be a weak compressor causing the vehicle to not rise.

With a bit more info we might be able to help you with this.

Originally Posted by PeterH

Hi AlfaMale, a few questions for you to try and work out what's going on.

Do you get any faults appearing on the nanocom or message centre?
Have you rebuilt the valve block at any stage?

At a guess it could be a fault in the valve block causing the vehicle to keep rising to wade height, could also be a fault in the driver pack .
If it was me I'd probably start with a valve block rebuild to at least rule that out, somehow air pressure is going into the air springs.

Are you allowing enough time (leaving a door open) for air pressure to build up enough before trying to raise the vehicle?
How long since the compressor was rebuilt?
Could be a weak compressor causing the vehicle to not rise.

With a bit more info we might be able to help you with this.

Hi Peter,

Thanks for your message.

Valve block was rebuilt by me maybe 3 years ago. I suspected the 'going into wade' problem may be a non-return valve issue but thought checking corrosion on the white plugs is an easier item to eliminate before i tore into the valve block.

Compressor had a new seal put in it maybe 3 months ago. I don't think anything was particularly wrong with it but I was chasing the always trying to go into wade mode problem and wanted to eliminate the pump. It seems healthy to me and certainly have had no issues with pressure lately. I can hear the pump running. I've tried leaving the door open for 5 to see if it jumps up - no luck.

Nanocom is picking up an "unknown fault" it previously would occasionally get a 'pressure switch not changing stat'

I will add that i've noticed the LH Rear always wants to stay higher than the rest of the car.

Thanks for the info, that is of some help.

So lets rule out the compressor for the moment.
With stuff like this, I always look for the easy answers first, before delving deeper if required.

First thing we need to work out why the system isn't pressurising.
If that has only started happening after you cleaned the corroded connections, it stands to reason there is possibly an issue there causing problems.
Might be worth having another look there and see if you can make those connections work properly.

Valve blocks usually last a few years before they need attention, but it's possible the valve block is at fault.
Have you done the soapy water spray test?
That will usually reveal any air leaks, spray all the connections on the side of the valve block looking for air bubbles, take off the silencer and spray there to see if any air escaping.
Spray around the top of the solenoids where they attach to the valve block, look for air bubbles forming.
Spray the connections at the compressor and also the connections to the air bags.
We are looking for any tell tail signs of air leaks which might point to leak issues.
The diaphragm can fail to seal and let pressure escape.
That's a good first step, it can be a process opf elimination with this.
Of course you need pressure in the system to do these tests, but even if the compressor is running, it should be enough to reveal any air leaks.

The fact that one corner wants to stay higher, I'm wondering if it might be height sensors playing up.

How old is the valve block driver pack?
They can start to play up with age and cause weird things like that to happen.

Another thing that can happen is the dryer media can start to get powdery with age and enter the valve block, leaving a powdery residue inside the valve block.
This eventually causes the seals to stop doing thier job properly and cause things to go a bit haywire.
I recently replaced my dryer cannister with a new one, very easy to replace.

Just throwing out a few thoughts here, but I would start with the soapy water test as a first step.
Also clear any fault codes and see if any new ones pop up.

Let me know how you go!
Cheers, Pete.

Originally Posted by PeterH

Thanks for the info, that is of some help.

So lets rule out the compressor for the moment.
With stuff like this, I always look for the easy answers first, before delving deeper if required.

First thing we need to work out why the system isn't pressurising.
If that has only started happening after you cleaned the corroded connections, it stands to reason there is possibly an issue there causing problems.
Might be worth having another look there and see if you can make those connections work properly.

Valve blocks usually last a few years before they need attention, but it's possible the valve block is at fault.
Have you done the soapy water spray test?
That will usually reveal any air leaks, spray all the connections on the side of the valve block looking for air bubbles, take off the silencer and spray there to see if any air escaping.
Spray around the top of the solenoids where they attach to the valve block, look for air bubbles forming.
Spray the connections at the compressor and also the connections to the air bags.
We are looking for any tell tail signs of air leaks which might point to leak issues.
The diaphragm can fail to seal and let pressure escape.
That's a good first step, it can be a process opf elimination with this.
Of course you need pressure in the system to do these tests, but even if the compressor is running, it should be enough to reveal any air leaks.

The fact that one corner wants to stay higher, I'm wondering if it might be height sensors playing up.

How old is the valve block driver pack?
They can start to play up with age and cause weird things like that to happen.

Another thing that can happen is the dryer media can start to get powdery with age and enter the valve block, leaving a powdery residue inside the valve block.
This eventually causes the seals to stop doing thier job properly and cause things to go a bit haywire.
I recently replaced my dryer cannister with a new one, very easy to replace.

Just throwing out a few thoughts here, but I would start with the soapy water test as a first step.
Also clear any fault codes and see if any new ones pop up.

Let me know how you go!
Cheers, Pete.

Hi Pete,

Thank you for your level headed response. Opened the bonnet and sure enough it was dumping air straight out through the diaphragm. I had a kit on the shelf so ran that through the valve block last night and is pressurising now.

I was convinced that I'd done something electrical because the only thing I'd touched was the connector. It was unfortunate that the seal it failed so completely as i was working on that but a valuable lesson that anything can happen at anytime and always go back to step one. The pump was running if it wasn't going into the air circuit it was going somewhere else.

Good note about the dryer canister. The diaphragm was heavily corroded and probably the cause of failure, there might be more moisture in the system than there should be.

Thanks again.

Lloyd

G’day mate,

I haven’t completely read your post, however, I am an avid P38 owner and I also live in Townsville.

Give me a call! I’ll come check it out with you.

0423 52 zero 4 five 7

Cheers
Keithy

That's very good of you Keithy, nice one!

Lloyd, glad you got it to pressurise, that's a very positive sign.
If you have rebuilt the valve block, you may find you have solved the problems you were experiencing.

Once you get it right it should be good for a few years at least.
I'll be interested to hear how it goes.
Pete.

Being new to P38 ownership I am always interested to read other peoples EAS problems and the possible solutions, and make a note of them, so thanks to the suppliers of the possible solutions here.

I don't know if my purchasing the new descant and cleaning out the old dryer canister was cheaper than a whole new unit, but that's what i did.

Range Rover P38 - Air Dryer Repair Kit - 4x4 Air Seals

I paid $70 for 2 recharges, in sealed plastic bags, and postage from UK of $36, in February 2023.

Andrew

My parts supplier only had the complete cannisters in stock, about $120 from memory, so I just got a new one.
But I will get a rebuild kit for the original one and have that on the shelf ready to go next time i want to change it over.
From what I've read, they are supposed to last the life of the vehicle, but in reality, the dryer media does start to break down after a while and releases fine powdery residue into the valve block, causing issues there.
Water in the system would shorten the life of the dryer media.
I think it's a sensible idea to replace every now and then as preventitive maintenence, I'd rather replace that (pretty easy job), than have to rebuild the valve block!