We were getting ready to go for a walk out by the lake and decided to take the Mercedes ML350. So, we hopped in and I turned the key… it just cranked over for a few seconds then stopped. I tried it again, same thing. I tried a few times more, but no love. So, we took the other car.
When I got home, I hooked up my OBD2 Bluetooth adapter and connected up my phone, so that I could use Torque to check to see if there was an error showing up on the car’s computer. Unfortunately, no check engine light and no error code.
I thought to myself, what could it be? I doubted it was not getting spark as I had replaced all of the coil packs right after we bought it as preventative maintenance. So, I figured it was most likely the fuel pump or a bad sensor.
I jumped on the web and went to MBWorld.org to see if anyone else had the same problem. One post had the same issue. He had taken it to a mechanic and they checked almost every sensor and problem that would cause the ML350 to not start. He said after 3 hours of labor and a tow to a different mechanic, the new mechanic checked the fuel pump fuse and that was it.
So, armed with a fuse chart I found online, I went out to check the fuses. Sure enough, the fuel pump fuse had blown. One 20 amp fuse later and the car started right up. I am not sure what caused the fuse to blow, it is possible the fuel pump is getting old and pulling more amperage to run, but for now, I am happy that is all it was. If it blows again, I will look into swapping out the fuel pump.
So, the moral of the story, check your fuses before taking your car in for service. It is easy and fuses are cheap.