Safe to driveDrivable, but watch it yourself
SPN 520738 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 what the second half of the code (FMI) means.
| FMI 5 | Transfer Case PTO Solenoid Command — Air Solenoid B Packs Relay Under Current Or Open Circuit |
| FMI 6 | Transfer Case PTO Solenoid Command — Air Solenoid B Packs Relay Over Current |
| SPN 520738 FMI 5520738/5 · 520738.5 | current below normal or open circuit |
| SPN 520738 FMI 6520738/6 · 520738.6 | 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.