Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hi, welcome to Just Answer. My name is***** the ML, it is normal for the starter to continue to crank the motor after you release the key if the motor does not start. If you have a crank/no start condition you may have a bad crankshaft position sensor or a bad fuel pump. A test for spark and fuel pressure needs to be performed to see what you are lacking. You should check the fuses in the main fuse box under the hood to see if any have blown but more often than not this problem will come down to either a bad crank sensor or a bad fuel pump.
Let me know if you have any questions.