Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hi, leaving the key on would not normally damage anything. The first thing I would suggest is that you check to see if the fuel pump is running while a helper cranks the motor. You will need to lay underneath the car and place your hand on the pump to see if it is running. If the pump is not running I would say the fuel pump relay has failed. If the pump is running when you crank the motor then I would suspect you have no spark from the coil. The most likely cause of no spark would be a bad ignition control module.
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