Neurotic EAS

[Saulman1010]

Well I thought I finally got my head around Rosies EAS when she thows thows me a curved ball.
EAS tries to raise to high level at random. Happend to me three times now. All in 50-60klm zone while driving. With no input (ie button pressing) from me.
I can cancel it back to normal height but it takes time to return.
I put an o-ring through the valve block a couple of months ago and a new compressor and apart from a slow leak overnight on nearside rear that i thought id trace and fix next service.

What the hell? Brains trust....help!

[Saulman1010]

**
Neurotic!

[Keithy P38]

G’day mate,

As soon as things start going crazy like that, there’s one thing I’ll preach until the cows come home.... EAS driver unit. That will be your issue.

Cheers
Keithy

[bblaze]

Mine also does weird **** when parked all alone at night, tuckeed away in the shed, goes high or low, very moody but always even.
But when driving it will stay in high mode until I ddo about 1km above 80kmh, then it drops back to normal, then after about 1km of under 80kmh it will raise to high again.
This can be stpped by locking the height with the button
Not sure if its supposed to work like that but it does
But I must say it seems the most happy when tucked away in the shed and it can do its own thing.
Only every found 1 error in the eas with nanocom and that was a faulty height sensor, cleared and hasn't come back yet
Now touching wood
cheers
blaze

[private]

Interesting fault.

I modified my EAS system because I wanted to be in control of what it was doing, rather than the other way around. This modification inhibits it from operating on the move, and prevents the 'wakeup every six hours and adjust to the lowest wheel height' phenomenon that's (to me) a real PITA and quite unecessary. Although it wouldn't be a fix as such for yours it may be something to think about once you've sorted the issue...

In terms of your specific problem I'd suggest you could have a connection/earth issue around the EAS control box under the seat. This may not be the problem you find eventually but it's where I'd start - uncommanded ride level changes on the move are more likely to come from there (IMO).

If you want to isolate the issue (ie. determine for sure whether it's from the EAS control or some under the bonnet problem) just put a meter or light tracer on the output from the EAS control to the inlet and exhaust valve lines. I wouldn't expect them to be operating at 50km/h, if they do then the issue is most likely to be at the EAS control box or its inputs (and if that proves to be the case we could go through some further fault-finding procedures). Inlet valve is pin 26 on the connector, exhaust is pin 9 (this is for the plug that connects to the EAS control unit located under the passenger's seat).

That's all from first principles, there is a fair bit of data around on how the EAS units operate and the problems others have had so a bit of research will most likely give you some common faults and fixes too.

BTW does the problem still occur if you have the inhibit switch in?

[Saulman1010]

Interesting fault.

I modified my EAS system because I wanted to be in control of what it was doing, rather than the other way around. This modification inhibits it from operating on the move, and prevents the 'wakeup every six hours and adjust to the lowest wheel height' phenomenon that's (to me) a real PITA and quite unecessary. Although it wouldn't be a fix as such for yours it may be something to think about once you've sorted the issue...

In terms of your specific problem I'd suggest you could have a connection/earth issue around the EAS control box under the seat. This may not be the problem you find eventually but it's where I'd start - uncommanded ride level changes on the move are more likely to come from there (IMO).

If you want to isolate the issue (ie. determine for sure whether it's from the EAS control or some under the bonnet problem) just put a meter or light tracer on the output from the EAS control to the inlet and exhaust valve lines. I wouldn't expect them to be operating at 50km/h, if they do then the issue is most likely to be at the EAS control box or its inputs (and if that proves to be the case we could go through some further fault-finding procedures). Inlet valve is pin 26 on the connector, exhaust is pin 9 (this is for the plug that connects to the EAS control unit located under the passenger's seat).

That's all from first principles, there is a fair bit of data around on how the EAS units operate and the problems others have had so a bit of research will most likely give you some common faults and fixes too.

BTW does the problem still occur if you have the inhibit switch in?
Its random havent found any common denominators yet. Will try inhibit switch.
I love the EAS system.on these cars but they can be trying at times.
Ive had the vehicle for 20 years and years ago I made and effort to chase down all the earth points and clean them up to resolve frequent globe fail warnings. You might be on the right track. Worth looking at. Then ill tackle a test light on the eas output. Thx for your ideas.

[prelude]

The raising and lowering around 80kph is default behaviour, at least it is one mine. Perhaps there were differences for certain parts of the world I am not sure. I like this system if only because on highway speeds driving in the low mode, especially with the arnott gen3 bags you feel almost like driving a real car :) Solid on the road, through corners as well and when on the backroads and cities with speed bumps you drive around in the higher mode which flattens those pesky bumps out quite nicely ;)

The driver unit is indeed a prime suspect, at least when a car raises when parked. The eas itself never raises the car when it is parked since you would need control over the compressor in theory, the air tank does not hold enough air to raise the suspension completely, at least not on my car but it has been modified. I can't even force my car to raise with the faultmate instructing it to do so without the engine running. Imho that rules out any if not most eas components except the valve block (a very particular set of leaks) or the driver unit actually openening a particular set of valves.

Also, for the op's problem; the car raising to high, would that be the top light or extra high mode? this can happen due to faulty sensors. When the car detects that it is grounded it will try to go even higher by pushing more air into the bags in a last ditch effort to get some (more)grip on one of the wheels. When your sensors are out of whack the eas computer might get a conflicting signal thinking it will need to raise. Since high mode is only allowed up to 50kph it won't activate above and should even drop down when crossing the 50kph limit.

-P

[Saulman1010]

thx prelude.
Ok, that would mean (trigger for extended) would mean that Im getting significant difference in reading from abs sensors- suggesting high grounding.
Hmmm interesting, for a while now, if I park Rosie with full steering lock, on the next start I could get an abs error wjen I drive away. Im wondering if I have a loose/failing abs sensor?

[Keithy P38]

The eas senses grounding by the fact the readings are higher than the target values and the system is unable to lower the vehicle, so instead it raises it to (in effect) lift the body off whatever obstacle it’s stuck on.

Cheers
Keithy

[private]

@prelude is quite correct, the two trigger speeds (IIRC) are ~50km/h and ~80km/h, both of these triggers should cause a lowering of the vehicle, not raising.

The inputs to the EAS controller are the four height sensors, brake, handbrake, doors, engine speed and road speed (not counting the compressor inputs, inhibit or up/down switches at this stage). the combination of these inputs and the software logic means that in essence the EAS controller should not alter the ride height of the vehicle upwards while the doors are open, the brake is on (for < 3min), there is no engine RPM and/or there is road speed. It may however reduce ride height in some circumstances with these inputs in an otherwise inhibit condition.

If the simple test earlier suggested confirms it is the EAS controller commanding the ride height adjustment up on the move then while there could be an issue with one or more of the ride height sensors it shouldn't be the primary fault - because the various other interlocks should prevent this from happening.

Again I reiterate that I say the above from first principles and from recollection. I could be wrong and would encourage some research on the way EAS works, but if it were mine that'd be the path I'd follow and the logic I'd use in order to determine the fault.

Carrying on from this and to my mind (assuming the test determines it's a commanded change to the valve block) the actual fault could be an faulty input to the EAS controller, or a faulty controller. The input fault could arise from connections (possibly intermittent, including earth issues) or sensor/data faults. This should be relatively easy to determine with some fairly ordinary measuring equipment.

[prelude]

@Saulman the abs sensor have no influence on the vehicle suspension afaik. Perhaps at most road speed is measured from the abs sensors but that should not cause anything to happen like this. Sensors that are not seated properly or too much dirt in the reluctor ring (mixed with braking dust that contains metal particles) can cause these errors. Also reluctor rings can break but that is not likely. Not sure as to why it would only happen on full lock though. Try reseating the sensors and checking for dirt on the reluctor rings. Be carefull with using a pressure cleaner in that area because you can actually blow dirt into the seals and that's an entire new headache when that happens :D

Keithy is of course 100% correct: grounding is detected when the sensors go past the max target value. This can happen with faulty sensors but is less common. Whilst driving the car could rise into extended mode but only when the speed is below 50kph.

private is also right in that there is a number of value's that need to be satisfied for the eas to move, either up or down. so again, a car that raises when parked is quite impossible because the engine speed input should be 0. afaik this is usually measured in pulses so a faulty contact should not be able to "fool" the eas that the engine is running so I tend to think that the problem should exist elsewhere.

-P

[Saulman1010]

Hight sensor must be the villain. Rosie did the raising thing 3 times in a 15min drive last weekend but not at all when locked in hwy mode. Must be a worn area on a height sensor giving random numbers.
At 350k its probably prudent to change all four.
Sighs heavily......
Mjs

[private]

I think they're just relatively standard carbon-based potentiometers so it's unsurprising that one (or more) have worn in that time.

If you wanted you should be able to identify which one is faulty even with a normal multimeter; there are four analog inputs from the sensors to the EAS ECU located under the passengers seat, I believe these are pins 2,3 (left rear, left front), and 22 and 23 (right rear, right front). These points should show a voltage between ~1v - <5v and they should all be approximately the same. If one is substantially different, or if the course of a short drive (or even just moving the car up and down while stationary) you get an intermittent or erroneous reading it's likely that's the faulty unit. If perchance you had a 'scope this would be much superior to a meter, but it's not essential IMV.

Also, FWIW, if you can identify the faulty sensor I believe you may be able to swap the units around in order to get them to use a different part of the carbon track and therefore get a new lease of life, but I've not tried this.

Personally I would change the sensor type completely, but that's another story!

All of this from first principles, others with specific experience may be able to give a more accurate view...

[prelude]

You can swap them over and it will work, but usually the problem returns quite soon.

Measuring the potmeters is best done by disconnecting them from the car and place an analogue meter on the leads, this way any change will be visible right away. Digital units are often to slow for this purpose.

I replaced mine with a new set from spain, reasonably priced and the job is quite easy. Just make sure you do not damage the rubber on the suspension itself. No matter if you break the sensor or bend an arm, they are provided in the new set :)

Cheers!

-P

[Saulman1010]

You can swap them over and it will work, but usually the problem returns quite soon.

Measuring the potmeters is best done by disconnecting them from the car and place an analogue meter on the leads, this way any change will be visible right away. Digital units are often to slow for this purpose.

I replaced mine with a new set from spain, reasonably priced and the job is quite easy. Just make sure you do not damage the rubber on the suspension itself. No matter if you break the sensor or bend an arm, they are provided in the new set :)

Cheers!

-PRosie doesn't behave as much in hwy mode. Must have a bad spot on a sensor.
Meh. Makes my life interesting.....until I try to get under the garage rollerdoor in extended mode....nearly got me the other day. Haha.