2016 Ram 2500 - P208E Code and Service DEF See Dealer Message

Question

Running down the interstate and got the 'Service DEF System' message on the EVIC along with a 150-mile countdown to 5 MPH limp mode. Scanned it and got P208E for Reductant Injection Valve Stuck Closed. I can hear the pump priming when I key on, but I'm worried it's a clogged injector or a DEF quality issue.

I checked the harness going to the doser and didn't see any obvious breaks or melted wires near the exhaust. The tank is about half full and I only use fresh fluid from the pump. This is my daily driver and I need it clear for a haul this weekend.

DIY_Denise · Accepted Answer

✅ Confirmed fix: Removed the DEF dosing valve and found it completely blocked with ammonia crystals. Used a digital multimeter to check resistance across the solenoid pins and it was within spec (approx 12 ohms), confirming the electrical side was fine. After a 20-minute soak in hot deionized water, the crystals cleared. Reinstalled, performed a stationary DEF system test using an Autel scanner, and the code cleared immediately. No more countdown.

Sparkplug_Sam · Answer

It's very common for the DEF injector nozzle to get completely encrusted in dry urea crystals. This blocks the spray pattern and triggers the pressure sensor to trip that code. You should pull the injector out—it's only one clip—and soak the tip in hot distilled water. Don't poke it with anything metal, just let the crystals dissolve.

2016 Ram 2500 - P208E Code and Service DEF See Dealer Message

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