Safe to driveDrivable, but watch it yourself
SPN 4008 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by International and Renault Trucks, and what the second half of the code (FMI) means.
| FMI 5 | Fog Light 2 — Right Fog Light Undercurrent |
| FMI 6 | Fog Light 2 — Right Fog Light Overcurrent |
| FMI 5 | Lever supply, short to ground. Repair: Check the lever, check the wiring between the unit and the component (30), check the control unit. |
| FMI 6 | Lever supply, short circuit. Repair: Check the lever, check the wiring between the unit and the component (30), check the control unit. |
| SPN 4008 FMI 54008/5 · 4008.5 | current below normal or open circuit |
| SPN 4008 FMI 64008/6 · 4008.6 | 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.