Ram 2014 with 6.4 codes Galore

[Paperboy4828]

This whole thing started about 2 years ago. Engine light on, starting with the dreaded P1004 short runner code. After many parts and a bunch of shop time, the plug and part of the wire harness for the short runner actuator was replaced, which seemed to fix the problem for a while. When it returned, the recommendation was to replace the PCM... at some $3,000 cost. I did not do that. I lived with the P1004 code, reset when it showed. Next came a P1239, unexpected engine oil temperature, Then P0116 unexpected engine coolant temperature. Latest is P0300 random cylinder mis-fire. The mis-fire may be related to the fuel pump, if I turn the ignition to the on position for 30 to 60 seconds, then start the engine fires up smoothly. One other item to note, the coolant temperature and the engine oil temperature I have on the dash display, and I can tell pretty quickly if the temperatures are not correct (like one or both on the bottom), when I see it, if I stop, shift to park, shut engine off, open and close driver's door, and restart, without fail the reading come back and seem to operate normally.

I have pulled the plugs on the PCM and carefully cleaned the plugs and pin strips, but it didn't seem to help. At first, I thought wiring or plug issues at the sending unit, but with all the seemly random issues, I now think that's unlikely.

So finally, to the question... Could it truly be the PCM is failing? With all these random electronic gremlins what would be other potential things should I be investigating? How prevalent are PCM failures? Is there a way to test the PCM? I had the dealer re-flash the PCM while working on the P1004 issue. Any help or insights would be helpful. I'd love to hang on the truck for a few more years, but these codes are driving me nuts!

 

[hunterdan]

The short runner valve could be something as simple as the actual valve isn't moving like it's supposed to. If it doesn't move, it'll throw a code. If the intake is gunked up, it could cause the valve to stick and potentially get the random code. Since the srv motor is on the front of the 6.4 intake, it's easy to pull the motor, and try moving the valve by hand. If it doesn't move by hand fairly easy (it doesn't move a whole lot) then it's likely the intake manifold just needs to come off and be cleaned. As for the coolant and engine oil temps, check the wires going to the coolant temp sensor and the oil temp sensor. Look for damage to the wiring and the connectors. Otherwise, might be worth just swapping out the sensors with some OEM replacements and go from there.
The misfires, if you're getting low pressure at start, sounds like a bad check valve in the fuel pump.

 

[Paperboy4828]

Part of the very expensive P1004 issue was first the purchase and install of a new runner valve actuator, then purchase and install of a new intake manifold. After spending all that money, still having the problem, the dealer said we need to change the PCM (ECM). To me it seemed like they were throwing parts at the problem wilt little regard to spending my money. So that when I stopped... more parts more money with no guarantee the problem would be fixed.

I'll carefully check the plugs and wiring at both temperature sensors, just odd that multiple sensors would have similar issues... I will also be checking grounds to the engine. Thanks!