rasheed

rasheed

Well-Known Member
My EAS is in good nick, slightly "lazy" FR height sensor but not much else. Can leave it parked for 2 or 3 days and height will not drop and so forth. However of late it occasionally (and randomly in terms of driving conditions as far as I can tell) hard-faults into failsafe, deflates all the bags,flashes all its lights and warns of total system meltdown. Clearing faults (all imaginable faults listed) just takes a few minutes and then all ok. At other times when stopped on the side of a slope its spontaneously risen to full height but a single touch on the button (not double) brings it back down again. So I'm guessing either the driver pack or EAS ecu are going?

My question though is, what actually goes? Has anyone ever opened either the DP or ECU and identified which components fail and is it DIY fixable? I do go off road quite a bit. Could it just be some dirt or moisture gotten in somewhere?
 
rasheed said:
My EAS is in good nick, slightly "lazy" FR height sensor but not much else. Can leave it parked for 2 or 3 days and height will not drop and so forth. However of late it occasionally (and randomly in terms of driving conditions as far as I can tell) hard-faults into failsafe, deflates all the bags,flashes all its lights and warns of total system meltdown. Clearing faults (all imaginable faults listed) just takes a few minutes and then all ok. At other times when stopped on the side of a slope its spontaneously risen to full height but a single touch on the button (not double) brings it back down again. So I'm guessing either the driver pack or EAS ecu are going?

My question though is, what actually goes? Has anyone ever opened either the DP or ECU and identified which components fail and is it DIY fixable? I do go off road quite a bit. Could it just be some dirt or moisture gotten in somewhere?
Click to expand...

All the driver pack does is take a low voltage signal from the ECU and switches the higher voltage needed to each electro magnetic coil, to pulse the four corner valves or hold open the inlet, exhaust or diaphragm valves. I dont know how it is circuited or if any of the circuits can interact. Maybe they can and that's what gives problems. It will be full of switching transistors, power transistors and diodes i would think. It is as far as i know not servicable the only way to find out if it is causing your problem is to buy a new one or fit a know good one. Around £150.00 for a new one. Think Data was operating on one but not heard any outcome yet. Lazy operation of EAS is usually down to low air pressure.
 
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The driver pack uses pulse width modulation to operate the solenoids, a high voltage pulse to pull the solenoid followed by a decreasing voltage pulse to hold the solenoid. there are power transistors and signal transistors and some I.C.s and electrolytics. It is possible to de-pot it, I've done it, but it's hard work. I haven't had time to scope the internals which are basically several identical circuits.
Your fault could also be deposits from the air dryer breaking up clogging the diaphragm etc.
 
Datatek said:
The driver pack uses pulse width modulation to operate the solenoids, a high voltage pulse to pull the solenoid followed by a decreasing voltage pulse to hold the solenoid. there are power transistors and signal transistors and some I.C.s and electrolytics. It is possible to de-pot it, I've done it, but it's hard work. I haven't had time to scope the internals which are basically several identical circuits.
Your fault could also be deposits from the air dryer breaking up clogging the diaphragm etc.
Click to expand...

Think it only holds exhaust, inlet and diaphragm valves that have the weaker springs. For the corner valves with the stronger springs it just pulses them so coils don't overheat. That is the ticking you hear from valve block.
 
wammers said:
Think it only holds exhaust, inlet and diaphragm valves that have the weaker springs. For the corner valves with the stronger springs it just pulses them so coils don't overheat. That is the ticking you hear from valve block.
Click to expand...

Within each click, there is an operate pulse followed by a declining trail of hold pulses but the whole thing lasts for a very short time before the cycle repeats if the ECU decides that the level is still not right. I have a picture of the wave form somewhere, if I can find it I'll post it:)
 
My money is on the air dryer breaking up and clogging things up. Sounds exactly like what has happened mine in the last few weeks. Check your exhaust air filter for all the white powder and change it along with the air dryer. Mine arrived today from p38 spares on ebay
 
Erm.. maybe I won't start dissecting the driver pack just yet. I'd be in way over my head by the sound of it. I like the dryer particle theory except that I only changed mine a few months ago with the stuff from rover renovations. if that's broken up already (where the original had lasted 14 years) i'll have a few choice words to say.

tony, the FR only sometimes rises slightly slower than the rest of the car (you wouldn't notice if you weren't looking for it) and again only sometimes rides very slightly lower than the rest of the car. most of the time it levels fine and also rises and falls normally. that's why i was thinking its the height sensor as opposed to lack of air pressure. a new sensor is on the wish list but some way down at the moment.
 
Datatek said:
Within each click, there is an operate pulse followed by a declining trail of hold pulses but the whole thing lasts for a very short time before the cycle repeats if the ECU decides that the level is still not right. I have a picture of the wave form somewhere, if I can find it I'll post it:)
Click to expand...

Yeah a pulse of full voltage to open and a slower reduction so the valve does not slam against the seat.
 
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