I have a 2008 Dodge Ram 1500 Mega Cab 4x4, 5.7L last week it started acting up.. when crossing RR tracks or hitting bumps or turning hard let it will shut down, the ETC warning will flash and it will sometimes go into limp mode when you restart, restart again and it will run fine. It is giving a DTC code of P1618 but only immediately after it shut down once you let it set or restart it a couple times the code clears and it runs fine. I downloaded the FSM and am trying to run the diagonistic recommended in it, I'm just not clear on where this circuit runs and on the location of the sensors it powers, does anyone have a diagram that shows where the sensors are so I can trace the wires and see if it's a short and run the voltmeter tests. The circuit runs Module Powertrain Control, Throttle body, Sensor Accelerator pedal Position, Sensor Crankshaft Position, Sensor Oil Pressure. Thanks!

 

have you checked the Throttle Body for excess dirt/grime? if not you might want to check that and all the sensor connections that go to it...

Might not be the wiring right off the bat... might be a bad connection and/or some cleaning needed in there.

 

I will check the TB when I get home.. I test drove it last night and it ran fine for about 10-15 mins then it started acting up.. same thing flashing ETC warning, shutting down as before. I noticted it occured when I hit a bump (crossing RR tracks, small pot holes) and when I made a hard Left hand turn. This time it also gave me DTC code P0642 as well as the P1618. I need some idea of where those sensors are located. and which one of the four connections at the Powertrain Control module is the C2 connection if anyone can help I would appreciate it. If the TB isn't it I will have to start funning that 5 Volt circuit

 

I found the problem with my 08' Ram ... the wiring harness that runs to the CKP sensor and Knock sensor is routed to the right of the Oil filter and rubs on the sharp edge of the engine. It had rubbed a pin sized hole in the wire that feeds the CKP, when I hit a bump it would make contact and shut the engine down causing the erratic voltage readings on the DTC codes..P1618, P0335, P0642... this could also affect the knock sensor so check there first if you have an issue relating to the CKP or Knock sensor. The best way to find it is to disconnect both sensors and feed the wires back up toward the alternator. a small hole is all it takes!