Just thought i would do a little update.
Last night..i did dive into the diagnosis...did alot of testing...And i started to focus on the ABS/ESP light coming on /fault ,,and not bothering with the "raised 900rev idle"...as i do think that the reason for the raised idle is because of adaptions beeing screwed up because of the faultcode appearing.
I tested some canbus stuff...the canbus controller in both ECU and RCL module is in good order(i did this test because of "guided symptoms in the Mercedes workshop manual i found at Startek.info.
Anywhoooo
I found a poor can wire in the right hand side door sill.It was taped up..and inside it...half the wire threads were broken..So i soldered it..and taped it up.I am going to check the canbus wires on the driver side tomorrow.Im really hoping im finding some faults there aswell.
Fault persisted after fixing the CanBus wire.
I have also noticed that the fault with the abs/esp light only appears after car has got up to driving temp..and when sitting idling for a minute or two...which also explains why the faultcode potenially plays havoc with the idle adaption settings...as you cannot do adaption reset above 60 degrees...."i think".
I also messed about with some actual values in the Abs/esp module...and i noticed one pid ..that said "Circuit 61>>0 volts...."....when car was running....so that lead me on a track..eventhough i do not know if the car has a circuit 61...neither do i know what it is...i cannot find any info about it...but on the w211"s...it has to do with Battery voltage"stuff.
One faultcode that also have appeared is the the Abs/esp module is missing can signal from the ECU.......
So...that got me thinking....i need to verify the powerfeed to the abs/esp module....And i basically messed around alot there,,back and forth...
But in the end...i reminded myself of...oh...i do remember the w210"s especially....are pretty delicate when it comes to voltage..And that lead me further to the fact that i know that the battery has been sitting in the car for A long time...
So i decided to test the battery.......i tested it first when mounted in the car.....its a 100Ah battery...830CCA /EN
Battery test came out : 560CCA available.....battery resting voltage...12.5.....Battery test result "!Battery good....Recharge"..
Okei...today...i just ordered a new battery....and after taking the old one out..i tested the old battery again...and the test result was 542 CCA available...>>12.4 >> Replace Battery-...
SO......putting in a new battery...have given me some hope....done some "random "searches on the interwebs now tonight..and it does seem that the batteries when turning this low in voltage..can indeed play havoc with the electrics in the w210"s.......found several threads with "similar" "faults....though it can be a coinsidence.....but at least...it was a good feeling to put a fresh new battery in the car....basically a good thing to do anyways
OF course this problem is not solved..and i do not think im that lucky with it beeing "just" a poor condition battery.I have also ordered a new K40 Relay..as this is a critical component...I have opened the K40 relay in the car..and i do think i saw some poor soldering points...And for now i do not want to solder it....There is more to the k40 relay that can go bad..than just soldering points..there are resistors in there aswell..so..for now..i am leaving it untouched
I will definetly come back with updates.And a video also at abit later point..i have done alot of video "clips" during this "diagnosis" session.
Im sorry for the messy and lenghty reply...