2016 Ram 2500 - P208E Reductant Injection Valve Stuck Clogged

Question

I'm getting the dreaded 'Service DEF System' message on my 2016 Ram 2500. This is the third time this month. The truck is currently in a 5 MPH derate countdown mode and I'm about 100 miles from home. I've been pulling a 10k lb trailer through the mountains so it's been working hard.

I scanned it and got P208E. I tried clearing the code with my basic OBDII reader but it pops back up immediately. The DEF tank is full and I only use Peak BlueDef. I can't hear the injector clicking when I'm under there during the prime cycle.

NightShiftNate · Accepted Answer

✅ Confirmed fix: The DEF injector nozzle was completely crystallized internally. Even though the outside looked clean after washing, the orifice was plugged with solid urea. I pull the injector, soaked it in a bowl of distilled water for 30 minutes, and then performed a 'DEF Reductant Doser Pump Override' test using a scan tool. The crystal broke loose and it started spraying a perfect mist. Reinstalled and did a forced regen to clear the derate timer.

RegenRogerD · Answer

Before you replace anything, check the wiring harness going to the doser valve. These trucks are known for harness rub-through near the frame rail. If the wire is frayed or grounded out, the ECM won't be able to pulse the injector and you'll get that stuck code. Also, check the DEF pump pressure; if it's not hitting 5 bar, the injector won't spray correctly.

2016 Ram 2500 - P208E Reductant Injection Valve Stuck Clogged

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