Do not driveTo the nearest safe stop
SPN 520226 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, Volvo and YaMZ, and what the second half of the code (FMI) means.
| FMI 12 | ⚠ Fewer running cylinders than minimum — engine shutdown |
| FMI 1 | Fuel leak in the high-pressure circuit - Fuel rail pressure low. Blink code: 1-5-6. Power will be reduced. Repair: Check the high-pressure circuit for leaks. |
| FMI 12 | Number of running cylinders below the minimum threshold, engine stopped - Not all cylinders running. Blink code: 1-5-4. The engine will not start. Power will be reduced. Repair: Check the connectors and cable of the engine cylinder injectors. |
| FMI 11 | ECU internal monitoring reported a fault, function monitoring level (MoF). Scan tool code: P1014. |
| FMI 3 | Voltage at LCM power input No. 1 (pin PC1 9) is above 30.5 V. Unit supply wire shorted to a higher voltage. |
| FMI 4 | Voltage at LCM power input No. 1 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. |
| FMI 1 | Fuel leak from high-pressure circuit (Low fuel rail pressure). Blink code: 1-5-6. Power will be reduced. Repair: Check the high-pressure circuit for leaks. |
| FMI 12 | Number of running cylinders below minimum limit, engine stopped (Not all cylinders running). Blink code: 1-5-4. The engine will not start. Power will be reduced. Repair: Check the connectors and cable of the engine cylinder injectors. |
Do not drive. Stop as soon as it’s safe to do so — don’t keep going.
The code is flagged critical: the manufacturer considers it unsafe to keep driving without checking.
This code alone cannot say what will fail next, so stop at the first safe opportunity and look at it on the spot.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.