E320User

Alright guys here is the problem I got going on: Car does not start sometimes.

Now let me elaborate, the car usually starts, but it doesn't start on random occasions. If I am driving and when I am slowing down, there might be a chance the car will turn off and not start up again (only cranks). Generally the fix to this is I just wait for about 15-45 minutes and it'll start again. When I turn the key it will just crank but not start.

I've taken it to my local independent shop and they told me that they found the fuel pump is not getting any power, okay simple enough. So they think it is the On board computer or the starter, so what they did was test if these were sending power to the fuel pump if the problem fails (If the computer/starter are sending power the light bulb they installed in will turn on, however if they were not it won't. What was found that the computer and starter were fine). So the computer and starter were not the problem, the next thing they said it might be the key that is malfunctioning and activating the security feature and shutting off the car(? wtf?)

Currently I'm still driving the car, oh and another thing is that it doesn't matter if its hot, cold, car been driven or just sitting, its failed on all those scenarios.

Right now i'm stuck trying to figure out what the problem is, I'm still leaning towards it being the fuel pump breaking down anybody have any ideas? Any input or advice would help, feel free to ask any questions and I'll do my best to answer them wholly.. Thanks in advance guys!

RichardM98

Since the car would cool down some after 45 mins these two statements seem inconsistent.

It seems like you have two choices. 1) start replacing parts based on probability and cost or 2) have the car's computer scanned for fault codes.

E320User

Sorry I didn't mean to make it sound like that it can cool down, sometimes it starts up again after I try right after it shuts off and sometimes it doesn't it's kinda a random thing. I think I will have no choice but to scan for a fault code ugh, although nothing is coming up as a malfunction, could a code still be tripped?

Joeker82

Sounds like a anti theft device malfunction. IMO

E320User

You think maybe the new key I ordered from mercedes benz could be setting it off? I thought so too, but if it was then it shouldn't shut off while I am stopped and in D waiting at a stop light...? Or would it?

RichardM98

The car's computer stores a number of error codes as well as a number of 'adaptation' values. To an experienced tech they can tell a lot about what's been happening.

On CAN bus car's everything is connected by a computer network which sends info back and forth. So it's hard to pinpoint a cause. So as mentioned even the anti-theft system could trigger a start problem or the DAS (Drive Authorization System) could be a problem.

I think the key is unlikely. I assume it was properly programmed by MB.

E320User

I guess I will have to take it to the dealership to get the cars computer scanned for error/fault codes, hopefully that'll be the end of this problem ><
Thanks for your replies/inputs guys!