LiteraCola
Junior Member
Good morning, everyone. I'm having a few issues with my 2012 Ram 1500 Hemi CC. The truck spends most of its time in the garage and only has around 60k miles on it. For the last few months I've been getting a P3400 CEL for Cylinder Deactivation System Bank 1 but I've just been manually turning it off until I decide whether I'm going to fix it or buy a tuner to disable it permanently. It has always run flawlessly while doing this... Recently, though, I threw a P0301 for Misfire on Cylinder 1, also having a very rough idle so it seems that cylinder 1 is totally inoperable. I've read multiple articles and threads concerning the misfire and haven't found much useful information. Mostly, the trucks from said threads were taken to the dealer and repaired under warranty or the threads were never resolved at all.
Since the issue arose, I have swapped coils between cylinder 1 & 3 (no change), tested all coils and all measured the same resistance, tested for injector power and pulse (all good) including injector resistance (also all good). All injectors are ticking at idle, though. I've checked compression on all cylinders (all within spec). I have tried unplugging the coil on cylinder 1 while idling and there is no change in idle so it seems, as I mentioned before, that cylinder 1 is just not firing. The only thing I have not done is remove the valve cover and inspect the rockers while turning the engine. Also, I have not pulled the IM to actuate the MDS solenoids as I do not have the required scan tool to do so. ***My oil level is good and I did an oil change about 2k miles ago, just in case someone asks "the obvious question".***
During my research, I found that when MDS is active, oil pressure is sent to the lifters on 1, 4, 6 and 7 and they collapse, coming out of contact with the camshaft... sometimes these lifters get stuck. I've also read that the lifter rollers sometimes seize, causing damage to the cam shaft. Now, I'm all for a lopey idle, but I want to do it on my terms!
Am I on the right track? Am I on my way to pulling the heads to replace the lifters? Any suggestions are appreciated.
Since the issue arose, I have swapped coils between cylinder 1 & 3 (no change), tested all coils and all measured the same resistance, tested for injector power and pulse (all good) including injector resistance (also all good). All injectors are ticking at idle, though. I've checked compression on all cylinders (all within spec). I have tried unplugging the coil on cylinder 1 while idling and there is no change in idle so it seems, as I mentioned before, that cylinder 1 is just not firing. The only thing I have not done is remove the valve cover and inspect the rockers while turning the engine. Also, I have not pulled the IM to actuate the MDS solenoids as I do not have the required scan tool to do so. ***My oil level is good and I did an oil change about 2k miles ago, just in case someone asks "the obvious question".***
During my research, I found that when MDS is active, oil pressure is sent to the lifters on 1, 4, 6 and 7 and they collapse, coming out of contact with the camshaft... sometimes these lifters get stuck. I've also read that the lifter rollers sometimes seize, causing damage to the cam shaft. Now, I'm all for a lopey idle, but I want to do it on my terms!
Am I on the right track? Am I on my way to pulling the heads to replace the lifters? Any suggestions are appreciated.
