P38 stuck in access mode - no fault shown

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J

jeffers

Member
Posts
85
Location
Cwmbran, Wales
Hi, my P38 has decided to stay in access mode no matter what I ask it for. The access mode light is permanently on and the height requested flashes for ever. The compressor is NOT running. I have checked that the compressor will run by removing the relay under the bonnet and using a piece of wire across the contacts and it runs OK. Also, if I remove fuse 44 and replace it the compressor runs for a few seconds then stops. If I plug in the easunlocker the pump will run and stop as required. I unplugged no 1 pipe and the back passenger side went to the bump stops and raised itself again to access level when I plugged it back in and started up again. Any idea what I should check next?
 
jeffers said:
Hi, my P38 has decided to stay in access mode no matter what I ask it for. The access mode light is permanently on and the height requested flashes for ever. The compressor is NOT running. I have checked that the compressor will run by removing the relay under the bonnet and using a piece of wire across the contacts and it runs OK. Also, if I remove fuse 44 and replace it the compressor runs for a few seconds then stops. If I plug in the easunlocker the pump will run and stop as required. I unplugged no 1 pipe and the back passenger side went to the bump stops and raised itself again to access level when I plugged it back in and started up again. Any idea what I should check next?
Click to expand...
Do the compresor check in the How To section at the top of the page. Otherwise you need the EAS diagnostic software.
I would guess you have a leak and the compressor is knackered. If the airbags are original, they will be leaking, the design life is 7/8 years 80Kmiles.
 
Checked the compressor and it is giving pressure, put a gauge on it and it maxed out at 90psi. I know that isn't enought, so I need a new compressor, but is that enough to stop it rising to normal height? Also, why doesn't the compressor carry on running to try to get the system up to pressure, it only runs for a few seconds and then stops. I thought it would keep running if it wasn't up to pressure.
 
Just used the easunlocker to drain the main pressure vessel and then tried the system again. I was expecting the compressor to run for some time before timing out or overheating. It still didn't run at all or if it did it had stopped by the time I got out of the car and put my hand on the pump. It still runs it I bypass the relay, does this still point to it being the compressor or is there other checks I should do as well?
 
jeffers said:
Just used the easunlocker to drain the main pressure vessel and then tried the system again. I was expecting the compressor to run for some time before timing out or overheating. It still didn't run at all or if it did it had stopped by the time I got out of the car and put my hand on the pump. It still runs it I bypass the relay, does this still point to it being the compressor or is there other checks I should do as well?
Click to expand...

Look in the "HOW TO" at top of page and go through things. There are reasons compressor won't run. And why tank does not fill.
 
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wammers said:
Look in the "HOW TO" at top of page and go through things. There are reasons compressor won't run. And why tank does not fill.
Click to expand...

I have been through the "How to" but my situation doesn't seem to fit what it says. The compressor does run manually and create pressure (90 - 100 psi) but doesn't seem to run when the system is in normal use. So, if I start up with the doors open the compressor doesn't even run. I'm happy that from your guide I probably need a new compressor anyway, but as it doesn't run when trying to follow the next part of the "How to" is there another problem?
 
jeffers said:
I have been through the "How to" but my situation doesn't seem to fit what it says. The compressor does run manually and create pressure (90 - 100 psi) but doesn't seem to run when the system is in normal use. So, if I start up with the doors open the compressor doesn't even run. I'm happy that from your guide I probably need a new compressor anyway, but as it doesn't run when trying to follow the next part of the "How to" is there another problem?
Click to expand...
You can overhaul the compressor for not a lot of cash.
Do you have the EAS unlock software? If you do, can you run the compressor from the software?
The compressor has probably given up as I said earlier, due to leaks, possibly it has over heated and the thermal switch is faulty which would stop it operating under ECU control.
 
jeffers said:
I have been through the "How to" but my situation doesn't seem to fit what it says. The compressor does run manually and create pressure (90 - 100 psi) but doesn't seem to run when the system is in normal use. So, if I start up with the doors open the compressor doesn't even run. I'm happy that from your guide I probably need a new compressor anyway, but as it doesn't run when trying to follow the next part of the "How to" is there another problem?
Click to expand...

It does cover your situation. Is there not something about checking the thermal switch. That will be the reason it will not run without being bridged. So you now know you need to refurb the comp and change the thermal switch. Or a new compressor it's up to you.
 
Thanks for your reply, but like I said earlier the compressor does run for a few seconds if I remove fuse 44 and then replace it, so does this not mean the thermal fuse is good? The compressor also runs without any problem from the eas unlocker software. I really don't understand why it doesn't run normally on start up.
 
Datatek said:
You can overhaul the compressor for not a lot of cash.
Do you have the EAS unlock software? If you do, can you run the compressor from the software?
The compressor has probably given up as I said earlier, due to leaks, possibly it has over heated and the thermal switch is faulty which would stop it operating under ECU control.
Click to expand...

Yes, I do have the unlock software and I can run the compressor from this. I dont think the compressor is "giving up" as it doesn't even attempt to start as for as I can tell.
 
Used the unlock software to run the compressor for 5 mins with doors open. Removed eas unlocker then closed doors and started enginge and up she goes to normal and high position with no problem. However, the compressor is still not running will now check the pressure switch. The pressure switch was fine. Unplugged the delay relay to check that and couldn't see any problem with it but when I plugged it back in it all started working. I guess it was a bad connection on the delay relay. I have now ordered some manual valves ready for the next time!. I want to keep my old compressor as a spare and will order a new one either from ebay ( http://www.ebay.co.uk/itm/RANGE-ROV...arts_Vehicles_CarParts_SM&hash=item416f8b05a3 ) or this one http://www.lrdirect.com/ANR3731-supplied-by-britpart-branded-dunlop.html. Has anyone any knowledge of what this Dunlop compressor is like?
 
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jeffers said:
Used the unlock software to run the compressor for 5 mins with doors open. Removed eas unlocker then closed doors and started enginge and up she goes to normal and high position with no problem. However, the compressor is still not running will now check the pressure switch. The pressure switch was fine. Unplugged the delay relay to check that and couldn't see any problem with it but when I plugged it back in it all started working. I guess it was a bad connection on the delay relay. I have now ordered some manual valves ready for the next time!. I want to keep my old compressor as a spare and will order a new one either from ebay ( RANGE ROVER P38 EAS SUSPENSION AIR COMPRESSOR AIR PUMP | eBay ) or this one ANR3731 - DUNLOP Air Suspension Compressor Rr P38 - Land Rover Parts Direct. Has anyone any knowledge of what this Dunlop compressor is like?
Click to expand...

£24.95 for a refurb kit from Symilise on fleabay and about an hour of your time.
 
Spoke too soon! Worked all day yesterday tried it today and all heights looked normal started her up and she went to access height and stayed there. Once again pumped up using eas unlocker and up she went. I have now removed the delay relay until my manual valves come and I can continue to try and find out what's going on. I'm still open to an ideas of what to check to find out why the compressor refuses to run?
 
I second Datatek. I suspect the thermal switch is dodgy and possibly the seal on the compressor piston itself is on its way out. The thermal switch can be replaced for about £3 - £6 depending where you go. Piston kit about £20. You can get both off SymliseP38 on a well known auction site.

If you can use the EAS software to force the compressor on and get her up to normal / extended height then do do and pull the delay relay under the passenger seat and see which corner drops overnight. Wammers How To is your friend there.
 
Grrrrrr said:
I second Datatek. I suspect the thermal switch is dodgy and possibly the seal on the compressor piston itself is on its way out. The thermal switch can be replaced for about £3 - £6 depending where you go. Piston kit about £20. You can get both off SymliseP38 on a well known auction site.

If you can use the EAS software to force the compressor on and get her up to normal / extended height then do do and pull the delay relay under the passenger seat and see which corner drops overnight. Wammers How To is your friend there.
Click to expand...

As said above - I have used the eas unlocker to get her up and I have pulled the relay. Unless I'm not understanding things correctly the fact that the compressor will run at will by using the eas software means the thermal fuse is fine and also the compressor whilst not pristine is giving enough pressure to both get to "high" and to cut off via the pressure switch when I did have it running yesterday. The problem seems to be that the ecu is not telling relay 20 to start the compressor correctly. With everything connected and the engine running, if I pull the delay relay and plug it back in the compressor starts and then stops after about 30 seconds now, yesterday it was working fine. I have even pulled connection 6 and drained the air receiver and still the compressor doesn't run for more than 30 seconds unless forced manually and then I get up to about 110psi in about 12 mins. Still stumped :( I will however put her on high and see if there is any drop in the morning.

Just resorted to looking at Rave and I see that my assumption about the thermal fuse is not correct. The compressor can be forced on even with the thermal fuse gone. Checked the thermal fuse and there is a 2 ohm resistance between the orange and black wires on the compressor plug which seems to be correct. So still no joy :(
 
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jeffers said:
As said above - I have used the eas unlocker to get her up and I have pulled the relay. Unless I'm not understanding things correctly the fact that the compressor will run at will by using the eas software means the thermal fuse is fine and also the compressor whilst not pristine is giving enough pressure to both get to "high" and to cut off via the pressure switch when I did have it running yesterday. The problem seems to be that the ecu is not telling relay 20 to start the compressor correctly. With everything connected and the engine running, if I pull the delay relay and plug it back in the compressor starts and then stops after about 30 seconds now, yesterday it was working fine. I have even pulled connection 6 and drained the air receiver and still the compressor doesn't run for more than 30 seconds unless forced manually and then I get up to about 110psi in about 12 mins. Still stumped :( I will however put her on high and see if there is any drop in the morning.

Just resorted to looking at Rave and I see that my assumption about the thermal fuse is not correct. The compressor can be forced on even with the thermal fuse gone. Checked the thermal fuse and there is a 2 ohm resistance between the orange and black wires on the compressor plug which seems to be correct. So still no joy :(
Click to expand...
The thermal switch is not a fuse, it's switch and should read zero or very near zero ohms.
 
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