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SPN 3216 — NOx at SCR system inlet

Safe to driveEnough to reach the yard

J1939 code SPN 3216. Below — how the fault is worded at the factory by DAF and SITRAK, and what the second half of the code (FMI) means in the standard.

DAF

FMI 18NOx upstream of catalyst too high value (extended period)

SITRAK

FMI 0NOx sensor reading too high. Scan tool code: P2201.
FMI 1NOx sensor reading too high. Scan tool code: P2201.
FMI 2NOx sensor reading not plausible. Scan tool code: P2214.
FMI 3Short circuit inside the NOx sensor. Scan tool code: P2200. Effect: Torque will be limited after 50 hours of operation.
FMI 5Open circuit inside the NOx sensor. Scan tool code: P2200. Effect: Torque will be limited after 50 hours of operation.
FMI 11NOx sensor stays in the not-ready state for too long. Scan tool code: P2204. Effect: Torque limited, MIL on, power may drop to 60%.
FMI 12NOx sensor reading not plausible. Scan tool code: P2214.
FMI 15NOx sensor reading not plausible. Scan tool code: P2214. Effect: Torque will be limited after 50 hours of operation.
FMI 17NOx sensor reading not plausible. Scan tool code: P2214. Effect: Torque will be limited after 50 hours of operation.
FMI 18NOx sensor reading too high. Scan tool code: P2201. Effect: Torque will be limited after 50 hours of operation.
FMI 19NOx sensor did not become ready within the allowed time. Scan tool code: P2200. Effect: Torque will be limited after 50 hours of operation.

What FMI means in J1939

SPN 3216 FMI 03216/0 · 3216.0data above normal range (most severe level)
SPN 3216 FMI 13216/1 · 3216.1data below normal range (most severe level)
SPN 3216 FMI 23216/2 · 3216.2data erratic or intermittent
SPN 3216 FMI 33216/3 · 3216.3voltage above normal or shorted high
SPN 3216 FMI 53216/5 · 3216.5current below normal or open circuit
SPN 3216 FMI 113216/11 · 3216.11root cause not known
SPN 3216 FMI 123216/12 · 3216.12faulty device or component
SPN 3216 FMI 153216/15 · 3216.15above normal — low severity
SPN 3216 FMI 173216/17 · 3216.17below normal — low severity
SPN 3216 FMI 183216/18 · 3216.18below normal — moderate severity
SPN 3216 FMI 193216/19 · 3216.19error in received network data

Can I keep driving

Safe to drive. Below — how much time you have and what happens if you keep going.

What happens if you keep driving

Time you have: Enough to reach the yard

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.

What to check on the spot

Fill the AdBlue tank. If it’s already full, the problem is dosing or reductant quality — you need a scanner.

Where to start

This code is often not the fault itself but a knock-on. If any of these is in the same readout, start with it:

Nearby: AdBlue / exhaust

Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.