← code lookup·All fault codes

SPN 4096 — NOx exceedance — AdBlue tank empty

Safe to driveEnough to reach the yard

J1939 code SPN 4096. Below — how the fault is worded at the factory by Knorr-Bremse EBS and MAN, and what the second half of the code (FMI) means in the standard.

Knorr-Bremse EBS

FMI 0Pressure control module, wheel 1, electronic circuit faulty

MAN

FMI 0Pressure control module, wheel 1, electronic circuit faulty

What FMI means in J1939

SPN 4096 FMI 04096/0 · 4096.0data above normal range (most severe level)

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.

Which codes follow

If the value really did go out of range, rather than a sensor circuit being broken, these normally light up after it:

They are not fixed separately — they go out together with this one. The list is deliberately short: only the links the reference is sure about.

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.