Dodge RAM Won't Start: DEF System Disables Engine

Had a very similar issue with my 2015 Dodge RAM diesel last winter. Have some experience with diesel engines and DEF-related problems, though not a professional mechanic. The symptoms match exactly what happened to my vehicle, engine refused to start and the emissions control system triggered warnings. Initially thought it was just low DEF fluid, but filling it up didnt solve the problem. Turned out the connection between the DEF tank and the injection system was faulty. Took it to an independent workshop specializing in diesel engines. They diagnosed a defective line from the DEF fluid tank to the dosing unit. The repair involved replacing the connection assembly and recalibrating the system. Total cost was 250€ including parts and labor. Modern diesel engines are quite sensitive about their emission standards compliance. When the DEF system has issues, they often go into a protective mode preventing startup. To help diagnose your specific case, could you share: Current DEF fluid level? Exact error code showing up? How long the problem has been occurring? Whether you noticed any warning lights before the no-start condition? This would help determine if youre facing the same underlying issue and whether your repair might be similar in scope and cost.

Last service was at 112000 KM and DEF fluid was topped up then. The error codes point to a DEF system issue, P20EE and P242F. The dashboard alert showed check engine first, then the DEF warning appeared. After refilling the DEF tank the injection system still shows problems. Local mechanic suggested the DEF injector might be clogged but hasnt diagnosed it fully yet. Tried clearing the codes but they came back immediately. The diesel exhaust system seems to be functioning normally otherwise, no excessive smoke or performance issues before this started. Getting an estimate this week for the repair costs. Hoping its just a sensor or injector issue rather than the entire DEF module.

Thanks for those details about the error codes and symptoms. Your situation sounds nearly identical to what I dealt with on my Dodge RAM. The P20EE and P242F codes typically point to SCR catalyst efficiency issues, which in my case was caused by a failing DEF injector. Even after filling the tank, the injection system kept showing problems because the DEF wasnt being properly sprayed into the exhaust. My mechanic initially thought cleaning the injector would fix it, but we ended up needing to replace both the injector and the dosing control module. The total repair came to 780€, which included: New DEF injector, dosing control module, system diagnosis, cleaning the SCR catalyst, resetting the emissions control system. One thing to check, make sure the DEF in your tank hasnt crystallized. This can happen if its been sitting too long and can cause these exact symptoms. If thats the case, the tank needs a thorough cleaning before installing new components. The good news is this type of repair restored full fuel efficiency and resolved all error codes permanently. Just ensure whoever does the work fully resets the system afterward, as the engine computer needs to relearn the new component parameters.

Thanks for the detailed info about the P20EE and P242F codes. Will get my mechanic to check the DEF tank capacity and look for crystallization first before replacing parts. You mentioned similar repair costs around 780€ which helps with budget planning. The service light came on about 2 weeks ago, followed by the dashboard alert for DEF system issues. Tank is now full but the injection system warnings persist. Will have them inspect both the injector and dosing module since those components solved your similar problem. Planning to get this fixed next week. The current error codes match yours exactly, so feeling more confident about the repair path. Good point about making sure they reset everything properly after the work. Glad to hear your repair restored normal operation, hoping for the same outcome with mine. Will update once I get final diagnosis and cost estimate. Really helpful to compare symptoms and repair details with someone who went through the same emissions control system problems. Thanks for sharing your experience.