Yet another EAS mystery

[rangerdanger]

All this recent talk about EAS problems must be contagious.
My symptoms are strange and I am running out of places to look.
I have a near new compressor, valve block, airbags and just replaced the driver block with a second hand one, and have replaced the timer relay with a yellow one so the car holds level overnight. No leaks at all. Pumps up from empty in 8 minutes. Tank holds pressure for weeks on end and car does not leak down overnight with the electronics turned off..
My problem: Car will adjust to normal height when starting, then the front will randomly adjust down a bit, then up a bit, then down a bit as if it is hunting for a height setpoint then overshooting. Consequently it consumes air and the compressor has to run. It then adjusts again (stopping the compressor briefly to do so) and continues this cycle at roughly 10 -20 second intervals. All this time the 'normal' led remains lit
Is it likely to be an ECU problem? Bad connection or earth somewhere? flat spot on the height sensors?
Any ideas welcome.
Troy N

[DieselLSE]

Almost certainly one or more height sensors. If you don't have access to a tester, try to work out which corner is causing the problem. But don't be surprised if another or all sensors need replacing.
But first I'd check that the height targets are set correctly and for this you will need a tester. It could be that one sensor is set either out of range or out of the differential range between the opposite sensor. I forget the limit, but I think the computer gets upset if the difference is as little at ten or so steps side to side.
I've stuffed around trying to reset sensors but have never been successful, though I understand others have been. I just bite the bullet and replace sensors now.

[TheTree]

I also think it's a sensor issue when you get the "Front End Dance" so as suggested I would be checking the settings and the sensors themselves

Steve

[PeterH]

I had the 'slow dance' occuring on mine, exaclty what you describe, it would find level and then I could hear the valve block expelling a few very short bursts of pressure lowering the front, then the compressor would run for several minutes, shut off, then the valve block would expel air again and the cycle would go on ond on.
On mine the culprit was one of the NRV's (non return valves). When I pulled the valve block apart, I found the middle valve had fallen apart.
I could not find any new NRV's, so I ended up getting a second hand valve block and took one of the valves from that.
I put new o rings on and put it back together, no more slow dance!
As others have said it could also be a faulty height sensor.
Something you might want to try is swapping the height sensors from side to side, effectively creating new height sensors, as they use a different part of the sweep to read height values.
I did this on mine, wasn't very hard to do.
You may need RSW software to recalibrate if the readings need adjusting, but on mine there was very little adjustment required.
Hope you get it sorted easily!

[rangerdanger]

Good feedback, I initially ruled out the front sensors as the front left is near new and the front right is 2004 replacement. I'm going to walk round the car while running and in neutral and check which corner does the raising and lowering. After driving today, it feels like it might actually be the back end lifting, giving the illusion that the front is dropping. If so, I'll swap sensors side for side, recalibrate then cross fingers.
I'm set up with EAS unlock and calibration blocks, so no problems there.


I hope it isn't a valve block NRV. Wouldn't there be some leaking down issues if it was?

[TheTree]

I also read the NRV's were the problem and also found this post somewhere !

Steve

" When you come to a stop and the speed falls below 1 mph both front valves open to equalise pressure across the axle, if one side is higher than the other this will cause the car to drop slightly. There will always be more pressure in the O/S than the N/S because the vehicle has self leveled to allow for the weight of the driver. So if your O/S is a little higher than the N/S to start with this movement will be more pronounced. As the pressure equalises the car will drop then the car will rise to the sensor settings. This will happen every time you stop in traffic. If you have a sensor that is not giving solid reads but the same in several positions this will cause the vehicle to go up and down. As the system attempts to adjust the height. But it can only do this untill the compressor starts as no exhausting of air is possible with that activated, as the exhaust tract is close by high pressure air acting on the bottom of the diaphragm valve and closing the exhaust port. The vehicle can only go up with compressor running it CANNOT go down. So if some people have dancing with compressor on they definatly have a leak in one of the front bags or air lines."

[daf11e]

When mine was dancing on one side it turned out to be a pinched o ring .

[TheTree]

It seems there may be more than one cause of this dancing.

First step seems to be to check for air leaks, either from bags, o-rings, airlines or NRV's

If that is all leak free then it has to be a sensor

Steve

[rangerdanger]

The car also feels like it does the raise and lower while in motion, at least by set of the pants feel on a smooth road. Therefore I'm thinking it won't be an NRV, the car also does not change height overnight, meaning it shouldn't be an air leak in a valve or bag.
At least that is my theory for the moment, will need to get a bit more scientific with it on the weekend.

[DieselLSE]

The Landrover workshop where I did my diesel conversion in 2010 would routinely reset the EAS on every P38 they serviced. They claimed that setting things back to normal just seemed to keep the car happy! It was also noticed by their customers who would ask what did they do to make the ride so much better, and be astounded when told they only pressed a few buttons to reset it.

[PeterH]

In my experience, leaking down issues (given there are no other leaks elsewhere) are caused by the valve block diaphragm.
Mine was dropping overnight and after checking all other possible areas for leaks and finding no evidence, I put a new diaphragm in the valve block and that sorted the issue.
They say you should not open the valve block (diaphragm section) without having a new diaphragm on hand, as they are very delicate and even the act of opening that area up can be enough to damage the diaphragm.
I know it can be a pain sorting through eas issues like this, but it's worth persisting, once I got mine right, it has been brilliant now for several months with no issues at all.

[benji]

If the ecu isn't getting a clean signal from the height sensor it will ' hunt' up and down for a good signal. You will see the front drop and stop rapidly.

If it's an air leak it'll go down and once it gets below the tolerance for that target height it will go straight up. .. it won't stop for a while.

Not sure if that helps.

Sent from my SM-G900I using AULRO mobile app

[mtb_gary]

Another way to verify whether it is an air leak is to either leave one of the doors or tailgate open overnight (effectively disables the EAS) alternatively if you can't leave the car open overnight such as being parked outside just remove the delay timer relay f4om under the passengers seat. Either method will disable the EAS sensors.

[rangerdanger]

Had a fun Saturday afternoon. Couldn't get the EAS unlock to talk, tried cleaning up the OBD plug etc, then finally swapped the original timer relay back in the position of the yellow relay I put in and it got comms straight away! One to watch out for....
Started with the rear height sensors, since they are originals. Swapped them and recalibrate the back end. Started the car, still the same problem. Appears to be hunting for height on the drivers side front, which is the older of the two sensors. Set about swapping the front sensors, followed by a recal of heights and all appeared well initially during the test drive, but upon pulling back into the driveway, started playing games again when stopped. Could be my imagination, but I think the initial dip starts on the passenger side now, ie followed the dodgy sensor.
The sensor arms appear pretty central on their stroke on the front, whether you swap right to left. Do they actually get to work on a new switch surface?
Next try will be replace that sensor with a new one. I'm surprise a 2004 vintage sensor would fail, after about 60k of use, but I guess it cops a bit of heat being tight next to the cat converter.

[Keithy P38]

Could it be another driver unit on the way out? They seem to be the cure for the other P38's!

On the note of yellow relay not allowing comms to the EAS ECU, I thought it was common knowledge! Maybe we need to put it in a sticky! You are right, with the yellow relay in place you won't get comms.

Good luck sorting it mate. I don't think it's a sensor personally!

Cheers
Keithy

[rangerdanger]

Keithy, just changed out the driver unit with a working second hand one last week, with no change, so I'm convinced that isn't where the fault is. After playing around Saturday, I have since done a few longer drives including towing a trailer and I can't detect the front end dipping while in motion any more, and the hunting at the lights is very minor. I hate to jinx myself, but I think it may be partly cured... although I will be replacing the older front height sensor regardless.

[flathead steve]

Mine was doing THE DANCE in the end I put new sensors and driver pack reset hieghts and all good . I did learn I had it set a bit high and it would throw a fault dropped it a fraz had no trouble for ages .