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Discussion Starter · #1 ·
I am trying to fix an issue with my 2010 Challenger SRT. The car currently has a 426 in it with a Vortec and a custom tune. The car has been running fine until yesterday when it died without warning on the highway. It would turn over and act like it wanted to start, but then wouldn't. I happened to have my Predator with me and checked the code. It came up with "P0688 ECM/PCM Power Relay Sense". I disconnected the battery for about 15 minutes to reset the PCM, but that didn't work. I also reloaded my custom tune, but that didn't work either. The code is now gone, but the car still won't start.

Obviously, the dealer won't touch it since it has so much aftermarket work done to it, so I am hoping that someone here could offer me some insight into what the issue is. Do I have a bad PCM?
 

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Fuel

I am trying to fix an issue with my 2010 Challenger SRT. The car currently has a 426 in it with a Vortec and a custom tune. The car has been running fine until yesterday when it died without warning on the highway. It would turn over and act like it wanted to start, but then wouldn't. I happened to have my Predator with me and checked the code. It came up with "P0688 ECM/PCM Power Relay Sense". I disconnected the battery for about 15 minutes to reset the PCM, but that didn't work. I also reloaded my custom tune, but that didn't work either. The code is now gone, but the car still won't start.

Obviously, the dealer won't touch it since it has so much aftermarket work done to it, so I am hoping that someone here could offer me some insight into what the issue is. Do I have a bad PCM?
Check to see if you have fuel .... That is make sure the fuel pump(s) is/are running. With your set-up you must have either a 2 or 3 pump set-up and or increased voltge to the existing pump( s). If you remove the lower back seat you should be able to hear and check the pump(s)
 

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Discussion Starter · #3 ·
Yup, that was it. I pulled the fuse 3 times and it looked fine. Decided to try a new fuse and it started right up. It had a very small break in it that was almost impossible to see. Guess I need to look at the wiring and see why the fuse blew out. Maybe the guage is too small.
 

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Yup, that was it. I pulled the fuse 3 times and it looked fine. Decided to try a new fuse and it started right up. It had a very small break in it that was almost impossible to see. Guess I need to look at the wiring and see why the fuse blew out. Maybe the guage is too small.
Not sure exactly how your fuel delivery system is set-up that is the number of fuel pumps and the wiring but I would comment that powering up the Fuel pump/s thru the OEM wiring is not what I would recommend as the OEM wiring is 15 Gauge ( That is what I have been told ) and as such is not large enought to handle more than the OEM fuel pump at normal voltage. For my self I have Fore/Arrington Fuel Hat with 2 Fuel Pumps and a Heavy duty wiring Harness and relay set-up ( the Heavy Duty wire Harness made a big difference on fuel Pressure ).
 
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