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Joined: Oct 27 2016
Posts: 18

After my initial intro a few hours ago I was feeling rather full of myself with what I considered not a major list of problems from the garage.

The Range Rover gods have decided to punish me and promptly threw me an EAS fault. When I bought the cars I had the full EAS Christmas Tree together with the merry little Ranger Rover with the arrow pointing up. I bought a cable from eBay and it showed the Pressure Signal Constantly High error. I cleared it and have since covered about 200 error free miles, albeit it has started to rise of its own accord a couple of times, so I thought maybe it was a one off. I took it for a run last night, the first time at motorway speed having fitted new tyres, and it went into to motorway/highway?! setting of its own accord and all seemed tickedyboo.

Having plugged in EAS Unlock again it is showing the same fault has reappeared. Most of the interweb points to a faulty Air Suspension Drive Box AKA Driver Pack. RSW suggests checking the Main Pressure Switch before replacing the driver pack.

1) Anymore suggestions?
2) How would I go about checking the main pressure switch? RSW says:

Main Pressure Switch. Check the functionality. If Pressure switch is normal, then problem is most likely sourced with the EAS Driver Pack.

Many thanks,

Mark

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Joined: Mar 12 2016
Posts: 647

Hi Mark, when it goes into motorway mode is that above 50Mph for more than 30 sec.? That's what it should do and return to normal height when driving slower than 35 Mph for more than 30 seconds.
As for the high pressure, maybe the switch (green) is duff, best is to take the unit out and check all valves (renew O rings). Seldom the driverpack is culprit.

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Joined: Dec 30 2015
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Be cautious, the errors that the RSW software show do not always mean what you think they mean. It often gives valve stuck open or valve stuck closed errors that are actually down to leaks. How does it behave normally? Does it stay at the correct height when parked overnight or does it drop either one corner or all around? Depending on the fault it sees it does different things to protect itself from damage. It might rise to maximum height, it might drop to the bumpstops or it might just stay where it is.

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Joined: Oct 27 2016
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Initially it rose to full height, but after I cleared it 10 days ago it went up and down properly ie motorway mode above 50mph and normal height under 35mph.

Today it is still sitting at what looks like 'normal' height - it doesn't look overly extended & it stays at the correct height overnight.

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I'd suggest keeping the cable and laptop in the car (although not connected as that can sometimes cause random errors) and just using it. All it may need is a bit of use as it looks like it hasn't had much for a while.

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Joined: Dec 29 2015
Posts: 728

Pressure Switch Stuck High is nearly always the driver pack. What's happened is, it's tried to fill an airbag, couldn't drive the appropriate solenoid open (but there's no way to detect that) so the pressure in the tank didn't drop, didn't see the pressure switch change state when it expected and got a bit freaked out.

If you use the RSW software you can use the height-setting page with the up and down buttons to test the solenoids and driver pack. When you raise or lower a corner you should hear the solenoids going, "tack tack tack tack", like that, about half a second apart. If you get "tack ... ... tack" with about a second gap in the middle, that corner solenoid isn't being driven. If you get "... tack tack ..." then the raise or lower solenoid isn't being driven.

Every single solenoid driver I've pulled from a breaker has had at least one intermittently faulty channel. It's probably why the vehicle was scrapped, weird untraceable intermittent EAS faults.

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Joined: Oct 27 2016
Posts: 18

Thanks for the feedback - I cleared it yesterday only for it to come back 3 miles later. I'll keep at it and also check the solenoids

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Joined: Dec 30 2015
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I had that error intermittently and Marty swapped out my driver pack for one he'd fixed. I haven't seen that fault since.

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Joined: Mar 09 2020
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Hi,

When it comes to fixing a driver pack for the EAS,
is there any info on the net on details?
I read here Marty fixed one.

thanks Paul.
PS I've just had the pressure signal constantly high message.

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Joined: Dec 30 2015
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The biggest problem is that the driver pack is encapsulated but not with the usual solid epoxy that is usually used for this sort of thing, but with a sort of semi flexible stuff. The solid epoxy is simple enough to remove with freezer spray which makes it go very brittle and crack so bits can be dug out, but this doesn't seem to work with the flexible stuff. With the valve block out it's very simple to check if all channels in the driver pack are working or if you have a different problem.

Marty did experiment with a driver pack of his own design but had problems when it started to get hot.

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Joined: Aug 19 2019
Posts: 82

A related question, has anyone found a source for new NRV's? To get 3 good NRV's I needed 3 different valve bodies for parts.

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Joined: Dec 30 2015
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Not found one yet, and one of mine is past its best. I noticed during the rebuild but I couldn't get three really nice ones out of the two blocks I had to hand.

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Joined: Dec 29 2015
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I looked at using an Arduino to drive six big MOSFETs. The normal controller pack provides about a 100ms pulse of 12V to the coil then PWMs it at 30% duty cycle at around 24kHz, using a bunch of opamps, transistors and passive discretes. I figured that since microcontrollers are as cheap as opamps and actually designed for PWM I mway as well just use that to drive everything.

I got a prototype pretty much working, drew a board, and then never really got a chance to finish it off, same old story. I'll put the files up on github if anyone fancies a shot at it.

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Joined: Dec 30 2015
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Didn't you also look into replacing the NRVs in the valve block with off the shelf ones too? Get anywhere with that?

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Joined: Jan 16 2016
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There was a guy off Landyzone called Datatek who did a write up on how to repair the EAS driver pack.
He also went on Rangerovers.net for a bit.
As I recall, I think it was a capacitor which caused the problem, but he gave precise details where to dig out the resin to get to it, so you don't have to dig out the whole lot.

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Joined: Jan 16 2016
Posts: 280

Found it:-

https://www.landyzone.co.uk/land-rover/driver-pack-problems.272816/

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Joined: Dec 29 2015
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I didn't get far with replacing the NRVs. My cunning plan was to find off-the-shelf "push fit" ones that could be machined down to fit the holes in the block, but I haven't really found anything that doesn't fall apart or have too small a hole up the middle to let enough air through.

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Joined: Jan 16 2016
Posts: 280

We have had this discussion before about NRV's, I think.
Someone said a variation of the Dunlop EAS system was used on Routemaster buses, and due to their widespread and continued use, spare parts should be readily available. Then the idea died a death for some reason.

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Joined: Dec 30 2015
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The Routemaster system pre-dates the P38 by very many years. The P38 system is a development of it. No idea if it uses a similar valve block though (and no idea where my local Routemaster main dealer is either....).

I'd seen the driver pack repair mentioned before but I'm not 100% convinced it is the problem. If it is simply the cap drying out (which isn't an unlikely problem) then rather than spending time digging the potting out why not just solder a replacement cap in parallel on the power feed? It's only going to be there for smoothing. I have found a driver pack where the ends of the cables weren't within the compound and they had started to corrode. I had an intermittent problem on one corner and that turned out to be a weak contact in the connector between driver pack and valve block. It's always possible that following the work the fault was actually in the connector and was cured by simply unplugging it and plugging it back in.