Safe to driveTo the nearest safe stop
J1939 code SPN 167. Below — how the fault is worded at the factory by DAF, Dongfeng and SITRAK, and what the second half of the code (FMI) means in the standard.
| FMI 1 | ECU power supply, pin C4 voltage too low |
| FMI 16 | ECU power supply, pin C4 voltage too high |
| FMI 18 | ECU power supply, pin C4 low voltage |
| FMI 1 | Alternator output voltage critically low |
| FMI 16 | Alternator output voltage too high |
| FMI 18 | Alternator output voltage too low |
| FMI 3 | System voltage above the upper limit for the actuator supply. Scan tool code: P0563. Effect: OBD limits torque immediately. |
| FMI 4 | System voltage below the lower limit for the actuator supply. Scan tool code: P0562. Effect: OBD limits torque immediately. |
Safe to drive. Below — how much time you have and what happens if you keep going.
The electrical system is not holding voltage. While the engine runs the alternator carries it; shut it off and you may not restart.
Next the lights go, then modules start dropping out and false codes appear all over the truck. Get to somewhere with help without shutting the engine down.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Check the battery terminals and earth strap — corrosion and loose clamps throw false codes all over the truck. Running voltage should be 27–29 V.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.