sure, one question, while I have the ecu off the car, can i spray contact cleaner on the board and put it back ?

 

I wouldnt. I would spray were it plugs in though and the acutal plug

 

Is your car starting up or not

 

it does after the ecu is cool and yes it does now but will stop starting up again after 30 mins of drive and when the car is switched off .

it is intermittent as said .

 

Looking at your REALOEM diagram,for your 530d, the fan is only installed in hot climate versions.... A non hot climate version without a cooling fan and a hot climate version with the cooling fan. They have different E boxes. Go back and look at RealOEM item #1, they list part numbers for both hot climate and non hot climate applications with build codes. Go to vin decoder and lookup your build setup.

From what you are describing your car is a Non option, S823A, Hot-Climate version 530d. So you would not have a cooling fan in the E box...

 

now what is hot climate version

I am sorry to sound noob but not sure what it means or what it is .

does it mean it is installed in hot countries?

 

Yes some vehicles did come with an E-box without ventalation but how many actually had it installed probably not many. The engine compartment gets hot so with the hot or cold climate package mainly intelled fan, oil cooler, water pump, inside options and software

 

Did you find a fan or do you not have one? Where you able to pull the IMs

 

After reading youre last post It does seem like it is a cooling issue.

 

no fan and checked it 10 times. I was sure i am not going mad as I have opened that area dozen times and never seen it

I am thinking of wiping the old thermal paste and replace it with a new one . would that work ? I have a cpu thermal paste so want to replace it with that