Safe to driveTo the nearest safe stop
J1939 code SPN 627. Below — how the fault is worded at the factory by Bendix ABS/ESP, DAF, Dongfeng, Knorr-Bremse EBS, MAN, Meritor (ex-WABCO), Renault Trucks and WABCO ABS/ESC, and what the second half of the code (FMI) means in the standard.
Bendix ABS/ESPDAFDongfengKnorr-Bremse EBSMANMeritor (ex-WABCO)Renault TrucksWABCO ABS/ESC
| FMI 2 | Input Voltage Excessive Noise (Temp.) |
| FMI 3 | Battery Voltage Too High; Ignition Voltage Too High |
| FMI 4 | Battery Voltage Too Low; Battery Voltage Too Low During ABS; Ignition Voltage Too Low; Ignition Voltage Too Low During ABS |
| FMI 5 | Battery Voltage Input Open Circuit |
| FMI 14 | Input Voltage Excessive Noise (Latched) |
| FMI 2 | ECU power supply, pin C4 incorrect shutdown (extended period) |
| FMI 12 | Power supply internal fault 1 (injectors, altered voltage) |
| FMI 2 | Failed to save ECM data from the previous operating cycle |
| FMI 12 | Injector voltage too low |
| FMI 3 | Power Supply. Not identified |
| FMI 3 | Power Supply - Not identified |
| FMI 0 | System Overvoltage (30A) (30B) |
| FMI 1 | System Undervoltage (30A) (30B) |
| FMI 14 | Interruption of Ground (31B) |
| FMI 17 | Interruption of Terminal (30A) |
| FMI 18 | Interruption of Terminal (30B) |
| FMI 2 | Mismatch between the charge levels of the diagonal supply circuits. Repair: Check the battery charge of all the speed sensors. |
| FMI 3 | Battery charge level too high. Repair: Check the vehicle voltage. |
| FMI 4 | Battery charge level too low. Repair: Check the vehicle voltage. |
| FMI 5 | ABS unit: open circuit. Repair: Check the continuity of the ABS unit supply wiring (X1/7, X1/8, X1/9, X1/17) (fuses F49 3 A, F28 20 A) |
| FMI 7 | Current to the EBS unit too high or too low, fault not stored. Repair: Check the EBS unit supply (positive on X1/7, X1/8 and negative on X1/10, X1/12). Check the fuses that belong to the EBS. |
| FMI 13 | VECU control unit relay: control fault. Repair: Check the VECU. The relay (R 43) is faulty. |
| FMI 3 | Overvoltage |
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.