If I disconnect the negative cable to the battery for 10 min
 

inorder to reset the computer on the ML 320 2002 will I loose security feature on the key or car and therfore will be unable to start the vehicle?
Please and thank you!

No.....................just make sure you have the radio code handy. My 2 cents. ;)

i have seen on ML only that if the battery is disconnected and reconnected the key that is in the ignition will be permanently lost from the aam, i have also seen this happen when the car is jump started and the jumper is connected with the key in the ignition, now keep inmind this always isn't the case, but something to keep in mind. we had a local independent car dealer who had this happen on several cars when they would try to jump it.

this happened to me once when I forgot to remove a key fob from my pocket and dove into the sea. other than that - replaced car battery once and worked on my car with battery disconnected multiple times - key fob stays in sync with aam.

I disconnected the negative cable without the key
 

ML320
in the ignition for approx 10min. Reconnected and just started the vehicle wothout driving it now the BAS & ESP light is illuminated???

I forgot to mention, turn the steering wheel all the way to the left then all the way to the right (or vice versa) to reset the BAS & ESP lights. My 2 cents. :D

Thank you Azinn, I assume
 

turn the vehicle to the left or right vica versa while the car is running?

the point here is to turn front wheels all the way both directions so car's electronics could "read out" both sides end positions through its sensors.
No need to turn the vehicle itself, but it might work since you would actually need to spin the steering wheel as mentioned above - all the way both directions

It's a lot easier if the truck is running.

do what you wish, just my suggestion to avoid an expensive problem, usually the aam and the key need to be replaced. just a good prventive measure.

I am so confused now I disconnect as you guys indicated drove
 

40km round trip no problems motor running at 80c
come home start up motor won't iginite - long engine turn, seperntine belt turning but won't start.
Disconnect battery car starts but dies adter 2 - 3 min
???

This sounds like CPS, crank position sensor failure. Vey common problem that leaves no codes. If you still have the original CPS in your truck, I would replace it before you get stranded. My 2 cents.

thanks for suggestion, Carson357 - I will keep it my mind. Basically my only wish for my truck to survive another year and I will be done with it. At almost 200k miles it is not fun anymore to keep it maintained well :)

Thanks guys!! I find the sensor at fault
 

Thanks for all the info guys.
The scanner shows crank position sensor

what did the scanner say? it is uncommon from my experience that a crank sensor will set a code