Code P0148 (high rail pressure)

[Dodgehtr]

I recently got this code it showed up while I was towing a trailer with my 2007 2500. First, I thought that it was an issue with the tune I was running #2 on Smarty Sr so I cleared the code and detuned to #1 this worked for awhile and then the code came back. After clearing the code a second time it cam back almost immediately so at this point I starting really paying attention to my gauges, I noticed as boost increased fuel rail pressure decreased( I think 15-20 PSI and i was at 10K on rail pressure) From what I have read it appears that it is either the FCA or the lift pump I recently changed the fuel filter and I hear the fuel pump run when I turn on the key. So I have a new FCA on order , an Air dog, and I also have a kit to alert me if the fuel supply pressure drops to <5 PSI. Do you guys think I'm on the right track or should I look at something else? Another thing is now that the trailer is dissconnected I drove the truck today and the check engine light went off I assume that the code cleared itself but I haven't hooked the smarty up to check yet.

[NickBeek]

Does your rail pressure gauge plug into the rail pressure sensor or are you reading rail pressure through the OBDII port? If your gauge is plugged in to the sensor directly, you probably have an issue with the harness there at the sensor. I had this issue  when I used a Quadzilla chip that plugged in at the rail sensor and intercepted the signal. A little di-electric grease in all the connections at the rail sensor fixed it up.

The check engine light will go out after a certain number of driving cycles with out the problem. The code may still be stored, but not active.

[Dodgehtr]

My guage does plug into the sensor.. I'll Check that out and clean it up just to be sure. Thanks for the ideas and I checked for codes with my Smarty and its all clear now so I'll see how it goes.

[NickBeek]

Those harnesses can be a pain in the butt. Clean dry and apply some dielectric grease, then makes sure they seat and click together well. I also found that zip ties helped keep the harnesses from moving around. Glad to help.