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Discussion Starter #1 (Edited)
Having read other threads am I right in thinking that the EDC switch on Nurburgring optioned cars should:

a. initially light up both P & S when you turn the ignition on
b. light up P or S depending which is selected
c. if a fault with the EDC has occurred, only light up in S position and not P + the dampers are locked in sport mode so changing switch position does not alter ride comfort (this may or may not be accompanied by an EDC FAILURE notice on the Check Control)

Now for the strange behaviour of my possessed car:<O:p</O:p

The switch only lights S on start up, P never lights up even when selected BUT there is a noticeable difference between P & S in damper settings (P feels like the car is suspended on 4 large bowls of blancmange - very shagged rear dampers are to blame - S is noticeably firmer). Could this just be a blown bulb in the switch or can this indicate some further EDC gremlins beyond 2 X badly leaking rear shocks?
 

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Mine has always lit up either P or S depending but never both when the ignition is switched on.

Haven't had a failure so can't help with default settings.
 

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Tubbs said:
Having read other threads am I right in thinking that the EDC switch on Nurburgring optioned cars should:

a. initially light up both P & S when you turn the ignition on
b. light up P or S depending which is selected
c. if a fault with the EDC has occurred, only light up in S position and not P + the dampers are locked in sport mode so changing switch position does not alter ride comfort (this may or may not be accompanied by an EDC FAILURE notice on the Check Control)

Now for the strange behaviour of my possessed car:<O:p</O:p

The switch only lights S on start up, P never lights up even when selected BUT there is a noticeable difference between P & S in damper settings (P feels like the car is suspended on 4 large bowls of blancmange - very shagged rear dampers are to blame - S is noticeably firmer). Could this just be a blown bulb in the switch or can this indicate some further EDC gremlins beyond 2 X badly leaking rear shocks?
If someone is close to you, you could try swapping switches to see what happens...

For what it's worth, don't think I've ever seen both lights on together.

I had my switche replaced as first one of the lamps stopped working and then the other just after the dealer replaced a rear shocker, but I since found out that they had forgot to top the system up afterwards.

Might be worth checking your level, especially if you say you have two leaking rears.
 

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Prutser said:
I thought shock absorbers were closed circuits. Are you saying they have some hydraulic hose connecting them to the powersteering circuit?
The EDC shocks are connected to the hydraulic reservour. The fluid is moved around the four corners via two solonoid valves on each shock. The damping is controled by which solonoid valve opens to allow the fluid to move around. There was a document posted the other day that described this.
 

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Gop-Dogg said:
The EDC shocks are connected to the hydraulic reservour. The fluid is moved around the four corners via two solonoid valves on each shock. The damping is controled by which solonoid valve opens to allow the fluid to move around. There was a document posted the other day that described this.
Does that also mean the powersteering will run dry when the shocks leak as bad as they currently do on mine? Or is the reservoir compartmentalized like the one for the brake and clutch fluid? 'cause the powersteering is really just fine.
 

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This topic would seem to confirm that the two systems share the same fluid, which they do.

Parts diagrams don't show every single component. If you looked at the diagram for the rear suspension you should see a pipe running to the front of the car.
 

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It looks we're (at least I am) drifting off-topic, but there is another thing about the illumination of the EDC switch. I took the switch apart and I saw it has an orange light to light up the letters "EDC" (presumably in the dark when the lights are on). However, mine never lights up. Is that bulb simply broken, or is this the car's way of telling me there's something wrong with the system?

:cheers:
 

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Prutser said:
I don't get it. I don't see any connections between shocks and steering. The steering hydraulic circuit as depicted here http://rust.mine.nu/bmw/showparts.do?model=HC91&mospid=45150&prod=19920500&btnr=32_0064&hg=32&fg=20&x=222&y=0 clearly shows a closed circuit between pump, reservoir and steering box. Are you sure shocks and steering are connected?
If you see the front shock drawing and the rear suspension drawings, you see the pipes running into/out of the shocks and from the accumulators. Unfortunately, the ETK drawings are not always connected in sequence, so it's hard to tell where the ins and outs from the drawings are going. :confused2
 

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Gop-Dogg said:
If you see the front shock drawing and the rear suspension drawings, you see the pipes running into/out of the shocks and from the accumulators. Unfortunately, the ETK drawings are not always connected in sequence, so it's hard to tell where the ins and outs from the drawings are going. :confused2
I thought the cables/hoses/tubes running from the front shocks were for the ABS sensor and the electrical EDC control.
I've read the EDC III service manual and some description of the system, but I can't find any reference to a hydraulic interconnection. hmmm

AFAIK the two solenoids are just electrical switches that control internal valves so the oil can pass more/less easily past the shock's cylinder and piston.
 

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How can a simple two position switch be giving so many permutations of illumination.
My switch and the other LE I tested show no illumination peculiarities at start up. It remains dark when P is selected and lights up only in Sport mode.
That is what I have thought it should do - now I am worried.

EDC front shocks are not connected hydraulically to any reservoir, I had a good look for the pipe connection when trying to work out why they were £600 each. :crying:

Great explanatory drawings and descriptions for the system BTW.
cherrsagai
 

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Hi There,

My UK LE has an EDC III Fault - but my experiences probably answer this thread quite well.

With regard to the EDC Selector Switch, - this lights up upon starting , but only on the programme that is selected - I.E. 'P' or 'S' = but not both.

MY EDC System is switching itself off at the moment - it's looking highly likely that one of the three acceleration sensors has had it.

But meanwhile, when the system switches itself off, I get the 'bong' from Check Control, the 'EDC NOT ACTIVE - OWNERS HANDBOOK' message on the dash, and the EDC Green Light goes out on the switch (whichever programme is currently selected), - to indicate the system is not functioning and is set permanently in 'S' - Sport Mode.
 

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FinalEditionE34M5 said:
Hi There,

My UK LE has an EDC III Fault - but my experiences probably answer this thread quite well.

With regard to the EDC Selector Switch, - this lights up upon starting , but only on the programme that is selected - I.E. 'P' or 'S' = but not both.

MY EDC System is switching itself off at the moment - it's looking highly likely that one of the three acceleration sensors has had it.

But meanwhile, when the system switches itself off, I get the 'bong' from Check Control, the 'EDC NOT ACTIVE - OWNERS HANDBOOK' message on the dash, and the EDC Green Light goes out on the switch (whichever programme is currently selected), - to indicate the system is not functioning and is set permanently in 'S' - Sport Mode.
That's exactly what I just had. Check last week's thread "Where are the G-sensors". The good news is that a faulty acceleration sensor is easily and accurately isolated by the BMW diagnostics computer.

:cheers:
 

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My understanding of the system is as follows.

The EDC switch lights up S or P depending on which is selected. I suspect the illumination is a function of the switch and not the EDC III computer but this should be easily checked. I've only once had a fault warning and I can't remember if the P went out or not.....in fact the P wasn't illuminating at all until recently!!

My guess would be if the illumination is irregular but the systems working fine then the switch is bust!

The SLS does take fluid from the power steering. On my car its feed to a small directional valve linked to the centre of the anti-roll bar above the diff. If the car is low the valve is opened letting high pressure oil into the , if its high then oil is bleed out, its that simple, no electronics. The accumulators are there to effectively increase the spring rate with increasing load.

On some of the bigger cars (the 750iL) an SLS system also works on the front shocks but I don't think its similar to the M5's system.
 
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