Safe to driveEnough to reach the yard
J1939 code SPN 3363. Below — how the fault is worded at the factory by Dongfeng and SITRAK, and what the second half of the code (FMI) means in the standard.
| FMI 3 | Short circuit to power or open circuit of the urea tank heater. Scan tool code: P3020. Effect: In cold weather the SCR system cannot thaw. |
| FMI 4 | Short circuit to ground of the urea tank heater. Scan tool code: P3019. Effect: In cold weather the SCR system cannot thaw. |
| FMI 7 | Urea tank heating malfunction |
| FMI 16 | Urea tank heating relay stuck |
| FMI 18 | Urea tank heater failed to defrost |
| FMI 0 | Over-temperature in the DEF tank heater valve circuit. Scan tool code: P3018. Effect: In cold weather the SCR system cannot thaw. |
| FMI 2 | CAN message signal error for the DEF level sensor. Effect: Torque limited, MIL on, power may drop to 60%. |
| FMI 3 | DEF tank heater valve circuit short to battery. Scan tool code: P3020. Effect: In cold weather the SCR system cannot thaw. |
| FMI 4 | DEF tank heater valve circuit short to ground. Scan tool code: P3019. Effect: In cold weather the SCR system cannot thaw. |
| FMI 5 | Open circuit in the DEF tank heater valve circuit. Scan tool code: P3016. Effect: In cold weather the SCR system cannot thaw. |
Safe to drive. Below — how much time you have and what happens if you keep going.
Urea dosing is interrupted and the ECU is counting. First the lamp, then a torque cut, then a forced crawl speed — the stages come in by engine hours, not all at once.
The truck will not die mid-highway, but the window shrinks with every running hour. Plan the repair now, not when the power is gone: an emulator or "deleting AdBlue" does not remove the problem, the codes keep stacking.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Fill the AdBlue tank. If it’s already full, the problem is dosing or reductant quality — you need a scanner.
This code is often not the fault itself but a knock-on. If any of these is in the same readout, start with it:
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.