Safe to driveDrivable, but watch it yourself
J1939 code SPN 2390. Below — how the fault is worded at the factory by International, and what the second half of the code (FMI) means in the standard.
| FMI 5 | Rear Fog Lights — Rear Fog Light Relay Under Current Or Open Circuit |
| FMI 6 | Rear Fog Lights — Rear Fog Lights Relay Overcurrent |
| SPN 2390 FMI 52390/5 · 2390.5 | current below normal or open circuit |
| SPN 2390 FMI 62390/6 · 2390.6 | current above normal or grounded circuit |
Safe to drive. Below — how much time you have and what happens if you keep going.
This is an electrical fault: an open, a short or a bad contact in the sensor circuit. The value it measures is most likely fine.
You can drive. But until the circuit is repaired this system runs blind and cannot warn you about a real failure.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.