05 Five Hundred Crank but no start sometime
 

My 05 five hundred crank but no start sometime. I have replaced fuel pump, fuel transfer pump, fuel pressure sensor, fuel filter. But still sometime happens. Does anyone have any idea or advice, please?

Did you check the fuel pump driver module ?

No I have not. Is there certain way to test to see if it’s bad? May be difficult for this case since it’s come and go?

It , the driver module, should be located in the pass side of the trunk. One check you might check is if there is power to the module when everything is working, then check if that power is present when the problem surfaces.

Thanks for advice but I can’t locate it in the trunk. I even looked underneath rear seat. Do you have any other idea where it could be?

I think I found it. It was underneath the panel on Rear pass side, side panel on C Pilar. Checked power and good. When it won’t start, voltage is kinda low like 7.7v instead of 10-13v.
https://cimg2.ibsrv.net/gimg/www.for...f26d2b289.jpeg

Make sure the fuel pump relay in the underhood panel is sending full voltage back to the driver module..

How (where) can check that?

In your vehicle owner's manual , in the "Specifications" section, are diagrams of what each fuse protects and locations of the various relays. There are usually 2 panels , one is usually located in the engine compartment (Power distribution) and one inside the vehicle. The relays are usually located in the engine compartment panel and some panel covers show which relay does what. Determine which one is the fuel pump relay and if and when you have the no start problem , temporarily swap the fuel pump relay with another relay for some non starting function.

Ok. Thank you for advise. Owners manual didn’t come with the car but I have located relay. I was not sure how and which prong to check with it. Sorry about that my comment may make you misunderstand what I tried to say. I will try it how you advise me when it happens again. Thank you