SPN 2596 — Vehicle Selected Maximum Road Speed Limit

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

Safe to driveEnough to reach the yard

J1939 code SPN 2596. No factory wording for it in the reference — below is the standard meaning of FMI.

Common FMI values

SPN 2596 FMI 02596/0 · 2596.0	data above normal range (most severe level)
SPN 2596 FMI 12596/1 · 2596.1	data below normal range (most severe level)
SPN 2596 FMI 22596/2 · 2596.2	data erratic or intermittent
SPN 2596 FMI 32596/3 · 2596.3	voltage above normal or shorted high
SPN 2596 FMI 42596/4 · 2596.4	voltage below normal or shorted to ground
SPN 2596 FMI 52596/5 · 2596.5	current below normal or open circuit

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

Time you have: Enough to reach the yard

This is not the fault, it is the reaction to it: the ECU is cutting power to protect the engine or the aftertreatment.

The limit will keep tightening until the cause is fixed. The code to chase is the one that triggered this, not this one.

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