Safe to driveDrivable, but watch it yourself
SPN 520231 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by KAMAZ, MAZ, SITRAK and Volvo, and what the second half of the code (FMI) means.
| FMI 2 | Electric fuel priming pump |
| FMI 3 | Electric fuel priming pump |
| FMI 4 | Electric fuel priming pump |
| FMI 12 | Electric fuel priming pump |
| FMI 2 | Electric fuel priming pump driver circuit fault - Overheating. Blink code: 3-2-6. |
| FMI 3 | Electric fuel priming pump driver circuit fault - Short to battery positive. Blink code: 3-2-6. |
| FMI 4 | Electric fuel priming pump driver circuit fault - Short to ground. Blink code: 3-2-6. |
| FMI 12 | Electric fuel priming pump driver circuit fault - Open circuit. Blink code: 3-2-6. |
| FMI 11 | ECU internal monitoring reported a fault, function monitoring level (MoF). Scan tool code: P101B. |
| FMI 3 | Voltage at LCM power input No. 6 (pin PC1 19) is above 30.5 V. Unit supply wire shorted to a higher voltage. |
| FMI 4 | Voltage at LCM power input No. 6 is below 7 V. Fuse blown in the battery box or in the fuse holder under the main fuse box. Open wiring between the LCM and the batteries, or wires between the LCM and the batteries shorted to ground. |
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.