Safe to driveEnough to reach the yard
J1939 code SPN 3031. Below — how the fault is worded at the factory by DAF, Dongfeng and SITRAK, and what the second half of the code (FMI) means in the standard.
| FMI 2 | AdBlue temperature F723 implausible (extended period) |
| FMI 3 | AdBlue temperature F723 short to power supply at ECU pin B38 (extended period) |
| FMI 4 | AdBlue temperature F723 short to ground at ECU pin B38 (extended period) |
| FMI 2 | Incorrect urea tank temperature signal. Scan tool code: P203B. Effect: OBD limits torque immediately. |
| FMI 3 | Short circuit to power or open circuit of the urea tank temperature sensor. Scan tool code: P205D. |
| FMI 4 | Short circuit to ground of the urea tank temperature sensor. Scan tool code: P205C. |
| FMI 0 | Implausible DEF tank temperature sensor signal: reading too high. Scan tool code: P205B. Effect: The SCR system does not work properly. |
| FMI 1 | Implausible DEF tank temperature sensor signal: reading too high. Scan tool code: P205B. |
| FMI 2 | DEF tank temperature sensor operation not plausible. Scan tool code: P203B. Effect: OBD limits torque immediately. |
| FMI 3 | DEF tank temperature sensor input voltage too high. Scan tool code: P205D. |
| FMI 4 | DEF tank temperature sensor input voltage too low. Scan tool code: P205C. |
| FMI 6 | DEF quality and temperature sensor short to ground. Scan tool code: P206A. Effect: Fan and warm-up control may misbehave. |
| FMI 14 | DEF tank temperature too high. Scan tool code: P2043. Effect: OBD limits torque immediately. |
| FMI 15 | DEF tank temperature sensor plausibility error, value too high. Scan tool code: P205A. Effect: Fan and warm-up control may misbehave. |
| FMI 19 | Invalid DEF temperature signal received over the CAN bus. Scan tool code: P205A. Effect: Fan and warm-up control may misbehave. |
| FMI 22 | DEF quality and temperature sensor signal above the upper limit. Scan tool code: P206A. Effect: Fan and warm-up control may misbehave. |
| FMI 23 | DEF quality and temperature sensor signal below the lower limit. Scan tool code: P206A. Effect: Fan and warm-up control may misbehave. |
| FMI 24 | Timeout of the DEF concentration signal. Scan tool code: P206A. Effect: Torque limited, MIL on, power may drop to 60%. |
| FMI 25 | Timeout of the DEF temperature signal. Scan tool code: P2042. Effect: Fan and warm-up control may misbehave. |
| FMI 26 | DEF quality and temperature sensor short to battery or open load. Scan tool code: P206A. Effect: Fan and warm-up control may misbehave. |
| FMI 27 | DEF quality and temperature sensor reported an invalid failure mode identifier. Scan tool code: P206A. Effect: Fan and warm-up control may misbehave. |
| FMI 28 | DEF tank temperature sensor plausibility error, value too low. Scan tool code: P205A. Effect: Fan and warm-up control may misbehave. |
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.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.