Elektrik: EDC4 Steuergerät überholen lassen

[andrewgrhogg]

I was directed to this thread from another thread. I am in the process of trouble shooting my own EDC shocks on my 2001 740iL. Im in the US and having google translate the forum, so it can be hard to do proper searches.

Some thoughts on the previous posts, from my research. I am in the process of creating a doc that covers all there is to know about EDC - because all the info is spread across many BMW docs and many forum posts, and much of the info is just wrong. Once i have finished i will post for feedback and review to see if i got anything wrong. But anyone that says anything is wrong will have to point to a source!

Here are a few bits of info that i have found so far, to add to the discussion:
1. The shocks are switched in pairs - two fronts together and 2 rears together. So if the front left is Hard then the front right is Hard. But the rear left and right can both be Medium while the front is Hard. It is up to the EDC control Unit.
2. The shocks are switched 4.5v and 1 amp per shocks, so 2 amps for front and 2 amps for rear. They are not always on and then grounded.
3. Each shock has 3 wires - 1 power line for each valve (there are two valves) and then 1 ground line.
4. The two valves are Medium and Soft. Hard is when both valves are off. Medium is when only the Medium valve is on. Soft is when only the Soft valve is on. The two valves are never on at the same time. Note that there is a default "valve" that is always on, which is how oil passes during the Hard mode. So the additional two valves are just increasing the total diameter of flow available for the oil to move through.

[olihaydt]

Dear Andrew -

I started this particular thread, because there are quite a few documents around (happy to send to you):
- procedure to learn of EDC is not functioning
- list of error codes related to the EDC
- info that EDC4 box may only be read out via ADS signal (usually requires old equipment with a real serial port)
- while the shocks themselves may be replaced (and somebody in Poland even refurbishes them), I haven't found anybody repairing the EDC4 box

So I understand your effort trying to consolidate the knowledge.

Anything we can help you with ?

You summary sounds about right ...

Oliver

[andrewgrhogg]

Hi Oliver,

Any docs you have on EDC, please send/share, especially on how to diagnose. I have read a lot of those already and most have key critical info missing. So you need to read all 10 and then aggregate. Pain in the butt and time consuming. That is basically what my doc is doing - aggregating all data from all BMW docs and all additional data found by users etc.

I have a list of error codes, but they are basic, like:
Valve fault, rear - Codes 80, 81, 82, 83, 84, 85

I note you had code 80 and some different text about the ground circuit. if you have any info on codes with more info on what they mean that would help a lot.

And of course once i have finished my doc, any input and feedback would be great. Hopefully later this week.

And FYI: My car was showing error 50 and 53 on the EDC and the EDC light comes on and stays on, but the shocks don't seem to change. I checked my wires to the front two shocks and i had a worn wire on the front left (drivers) shock. I will repair that tomorrow, reset codes and go for a drive and see how it works.

Quick update...i started stripping back the black exterior cover for the 3 wires to the shock. As i do this the yellow, red and white insulation on the 3 wrires inside is just crumbling and falling off. So now i have the shock wire with about 2" of bare wires and no insulation - i have not cut any of the wires. Using my variable DC power supply ( https://www.amazon.com/dp/B08HYK2ZW3...roduct_details) i have fed 4.5v/1amp to each of the red and yellow wires, with white as the ground. One valve you can easily hear switching. The other valve im not sure. Tomorrow i am going to try the same test with the right front shock and see if i can hear both valves triggering. If one is silent than ill assume the left shock is fine and then i will use "liquid tape" to seal the bare wires on the left shock and then clear codes and see what happens.