I need some help




http://www.mercedesmedic.com/mercedes-wont-start/
More guidance on checking fuel pump and pressure
https://mbworld.org/forums/clk-class...not-start.html
Good luck
Last edited by james clk430; Oct 27, 2016 at 09:16 PM.




Voltage supply from engine control module (N3/10) is missing.
Malfunction of drive authorization system (DAS) .
Fuel pump electrical wiring circuit defective.
Couple of suggestions:
Best way to check fuses is with a multi-meter, set to read voltage. With the negative lead to ground, on the top of the fuse, with the positive lead, test the metal contacts on the both ends for 12 volts. This method enures that the circuit has voltage input and that the fuse passes it through. Note: Just looking in the fuse window is not sufficient, as the fuse contacts may be corroded, due to dissimulator metals in contact (e.g. specially in high amperage circuits).
You can also probe the relay socket with the volt meter. The relay has 2 circuits. The diagram of the circuits and associated pins should be diagrammed on the relay's cover. The engine control module should power the control circuit (i.e. coil). With the relay removed and the key turned to the position where the fuel pump should be operating, there should be 12 volts present on 1 of the 2 socket connections. The side with no voltage goes to ground, which then can be checked with the meter set to read ohms. Similarly, the other 2 socket connections, that switch high power to the pump motor, can be checked as well.
Voltage supply from engine control module (N3/10) is missing.
Malfunction of drive authorization system (DAS) .
Fuel pump electrical wiring circuit defective.
Couple of suggestions:
Best way to check fuses is with a multi-meter, set to read voltage. With the negative lead to ground, on the top of the fuse, with the positive lead, test the metal contacts on the both ends for 12 volts. This method enures that the circuit has voltage input and that the fuse passes it through. Note: Just looking in the fuse window is not sufficient, as the fuse contacts may be corroded, due to dissimulator metals in contact (e.g. specially in high amperage circuits).
You can also probe the relay socket with the volt meter. The relay has 2 circuits. The diagram of the circuits and associated pins should be diagrammed on the relay's cover. The engine control module should power the control circuit (i.e. coil). With the relay removed and the key turned to the position where the fuel pump should be operating, there should be 12 volts present on 1 of the 2 socket connections. The side with no voltage goes to ground, which then can be checked with the meter set to read ohms. Similarly, the other 2 socket connections, that switch high power to the pump motor, can be checked as well.
Thank you very much I'm going to be checking everything right now its just so crazy that it would go out like that this car I've owned 4 about 5 years now and this is the only prob it's ever had I hope I can find something out cause this sucks
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I had a similar issue where the car would crank and crank then eventually start. Turned out to be dirt between the relay contact inside the cover. You could try opening the relay black cover up and sliding a piece of fine sand paper between the contact points to clean them inside.
I had a similar issue where the car would crank and crank then eventually start. Turned out to be dirt between the relay contact inside the cover. You could try opening the relay black cover up and sliding a piece of fine sand paper between the contact points to clean them inside.








As suggested, if the relay socket is not getting either the required control voltage or the switched contacts, that provide 12 volts down steam to the fuel pump, would would go a long way to isolate your fault.
Did any of the shops check for stored diagnostic trouble codes, using the MB Star Diagnostic System?
If so, forward the DTCs along, because it will would have suggested further DIY trouble shooting and repair measures.



