My '00 W210 E-200K will not start after being in storage for a period of three months approx. During that period the battery died completely. I have fitted a new battery however when I insert the key it registers ok (I can hear the usual buzz) and most of the warning lights come on. However the MIL doesn't ligth up, the fuel pump doesn't run as it should for a few seconds and when the key is turned to "start" position it doesn't do anything. I have plugged a scanner into the 38 pin diagnostic socket but it displays a connection error which looks like there is no power to the ecu. (Something I have experienced on another vehicle recently).
Also, I tried to tow the car a short distance (it has manual transmission) to no avail but I did notice that the rev counter did not register any revs when the engine was turning indicating maybe no spark pulse.
All fuses have been checked and found to be ok.
One other thing of note is that when the ignition switch is turned on the main engine cooling fan ramps up to full speed and runs until key is switched off.
Does anybody have any ideas what might be wrong? I have tried to include all know info, hopefully I haven't confused the issue.