It sounds like a discrepancy in height sensor readings.
If you have a diagnostic tool for the car you can monitor the height settings while the car is running and stationary.
👍

 

It sounds like a discrepancy in height sensor readings.
If you have a diagnostic tool for the car you can monitor the height settings while the car is running and stationary.
👍

Thanks. I don't have a diagnostic tool. Would you recommend heading to a landrover repair shop and ask them to confirm that my height sensors are okay? They can test and confirm it?

Btw somethign odd I forgot to mention in my post:

• Updated:
  • Sometimes after several hours of standing, the front of the car rises by itself to off-road height. As soon as I open/close a door or start the car it immediately drops back to normal height.
  • Other times, instead of rising, the car drops during standing. Then it takes quite a long time for it to reach default height again, but it always does eventually.
  • Sometimes it seems to hold the height steady for 1-2 days.

 

Have you been into the foot wells and removed the kick panels if not already and removed the connector blocks and hard wired each connector in turn?
The pollen filter on this models leaks water into the foot wells via the heater body and drips water onto the connectors causing a host of issues.
The height sensor readings and behaviors can be read using the appropriate daig tool of the repair has the correct diag suite. 👍

 

Rising while parked is most likely a small leak on the solenoid valve tips. This allows tank air to inflate the bags slightly, but will not show up externally with soapy water.

Dropping while parked is the self-levelling. To prove this after stopping the car & switching off, wait 2-3 mins for it to finish initial levelling, and then remove the timer relay un der left front seat. If it still drops you have leaks somewhere.

As suggested above, the continuous pump cycling & adjusting is usuall large differences in left-right sensor values. They need to be within 5-bits on the diagnostics.

• The reason is every time you stop at lights, it opens both front valves to balance the front L-R. After that if the sensors are way out, it tries to adjust again & cycle repeats. If it needs to lower, this will always cause the pump to stop-start, because the system cannot exhaust while the pump is running.
• Also if there are valve tip leaks, the bags tend to inflate when the pump is running, hence it rises when the pump runs & then adjusts down after stopping the pump !! i.e. it cycles on-off.

 

Rising while parked is most likely a small leak on the solenoid valve tips. This allows tank air to inflate the bags slightly, but will not show up externally with soapy water.

Dropping while parked is the self-levelling. To prove this after stopping the car & switching off, wait 2-3 mins for it to finish initial levelling, and then remove the timer relay un der left front seat. If it still drops you have leaks somewhere.

As suggested above, the continuous pump cycling & adjusting is usuall large differences in left-right sensor values. They need to be within 5-bits on the diagnostics.

• The reason is every time you stop at lights, it opens both front valves to balance the front L-R. After that if the sensors are way out, it tries to adjust again & cycle repeats. If it needs to lower, this will always cause the pump to stop-start, because the system cannot exhaust while the pump is running.
• Also if there are valve tip leaks, the bags tend to inflate when the pump is running, hence it rises when the pump runs & then adjusts down after stopping the pump !! i.e. it cycles on-off.

I am having the same issue with it rising. Park it and it goes from standard to offroad plus!! Start it and it lurches back down to standard. This is the whole car. How do you fix air going past the valve tips if that is my problem too?

 

I'm not sure there is a diagnostic for the pressure switch. If there is, test it. If not, replace it. There isn't much else that would make the compressor run so often without leaks (which you have checked).

 

The only way to test it, is to add a gauge to the tank feed & then see when the pressure switch changes state.

 

Thank you for the response guys, what I got so far:

1. Remove timer relay under the left front seat and see if the car dropps
2. Read out values from the height seonsors. They must correspond on both sides (need to drive to the repair shop)

What I did not understand:
1. "pressure switch". <-- where is it and how does it look like?
2. "add gauge to the tank feed & then see when the pressure switch changes state" <-- where is the tank feed?

Thanks

 

Pressure switch circled. It cuts off the compressor when there is sufficient pressure in the system. ANR3902

You should check out this page. Lots of great info. Not entirely perfect however. https://paulp38a.com/range-rover-p38/eas-valve-block-renew/

 

How old are the airbags? They can develop cracks similar to old tires. If leaking where folded against the mandrel a leak may not be identifiable by the bubble test. The good news is new Dunlop bags are available at a reasonable price.

 

Bags are quite old (i dont know how old) but i assumed that when bag is leaking then the car should consistently drop on the respective side, which is not the case.

 

Being a older technician I can say one thing to you, TODAY so called factory trained morons only know how to remove and replace today they do not know how to REBUILD anything nor do they know how to REPAIR just remove a unit and replace it. Now with all this crap computer controlled whatever it has gotten worse and ONLY triple the repair costs for customer even their so called REPAIR SHOP MANUALS do not show or tell a person how to "REPAIR" anything they just show pics and imply remove and replace so much for today's progress "BACKWARDS" using uneducated morons from top to bottom
they cannot think or know if the computer code does not say anything they are lost then they just R&R until they find a solution at your expense $$$$$$$$$$$$$$$$

 

Using a small paintbrush yesterday I applied soapy water also on the very bottom of the valves (where they connect to the housing) and I could see bubbles comming out:

It is the very first valve:

From this page: https://paulp38a.com/range-rover-p38/how-eas-works/ I understood that this is the "exhaust valve". Can its leakage explain my symptoms?

Nevertheless of course I will start now with repairing this leakage and continue from there.

 

Yes that's the exhaust valve. Leak there should not usually impact anything, but it usually implies corner valves are leaking internally to the exhaust valve. The issue is almost certainly the thin o-ring on the valve tube inside.

For the "rising while parked" question look at the EAS air diagram.

• NRV-1 should be holding the tank pressure.
• NRV-2 will be open due to tank pressure
• NRV-3 will be closed with no pressure on it unless NRV-1 is leaking.
• The main gallery between Inlet & Corner valves should be low pressure, unless any valve(s) allow tank or corner pressure into the gallery.
• Hence leaky valve tips on Inlet & Corners allow it to rise based on tank pressure.

The diagram also helps explain other possible air paths due to leaky valves, etc.

 

IMHO it's unlikely to burst the airbags. At standard height they will be approx 60psi each. Even with a full tank at 140psi, think about the volume of air. Tank holds 10 litres, so that's a max of 2.5 per airbag, but as the system equalises pressure, only about half the air will go into the bags.

My guess is the bags will get maybe an extra 1-1.5 litres which should be ok. . . . . . unless they already are aged & worn.

Sounds like you need to bench test the valve block & see if it is the valve tips, or another issue.

One of my P38's has an ignition switched relay to disconnect the feed to the timer relay. That disables any leveling & means no messing under the seat. Also diagnostics still connects. Only the rear rises on mine, and usually no more than 2-3 inches.