Safe to driveTo the nearest safe stop
J1939 code SPN 157. Below — how the fault is worded at the factory by DAF, Dongfeng, Foton, Isuzu, KAMAZ, MAZ, Renault Trucks, SITRAK, YaMZ and ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.
DAFDongfengFotonIsuzuKAMAZMAZRenault TrucksSITRAKYaMZZF AS-Tronic
| FMI 0 | Fuel pressure F648 pressure too high |
| FMI 2 | Fuel pressure F648 invalid or missing signal |
| FMI 3 | Fuel pressure F648 short to power supply at ECU pin A29 |
| FMI 4 | Fuel pressure F648 short to ground at ECU pin A29 |
| FMI 16 | Fuel pressure F648 pressure too high (actual above setpoint) |
| FMI 18 | Fuel pressure F648 pressure too low (actual more than 100 bar below setpoint) |
| FMI 0 | High-pressure fuel rail safety valve open |
| FMI 2 | Fuel pressure signal stuck (not changing) |
| FMI 3 | Short circuit to power supply of the fuel pressure sensor. Scan tool code: P0193. Effect: Engine speed is limited. |
| FMI 4 | Short circuit to ground or open circuit of the fuel pressure sensor. Scan tool code: P0192. Effect: Engine speed is limited to 1400 rpm. |
| FMI 16 | Fuel pressure too high. Scan tool code: P0190. Effect: Power limited, the engine runs unevenly. |
| FMI 18 | Fuel pressure too low. Scan tool code: P0190. Effect: Power limited, the engine runs unevenly. |
| FMI 18 | Insufficient fuel rail pressure. Scan tool code: P0190. Effect: Power limited, the engine runs unevenly. |
| FMI 0 | Common rail pressure fault (1st stage) (P0088) |
| FMI 2 | Common rail pressure fault (Excessive pressure feed in pump) (P0089) |
| FMI 3 | Common rail pressure sensor fault (high voltage fault) (P0193) |
| FMI 4 | Common rail pressure sensor fault (low voltage fault) (P0192) |
| FMI 3 | Rail fuel pressure sensor |
| FMI 4 | Rail fuel pressure sensor |
| FMI 15 | Rail pressure sensor: signal offset out of tolerance |
| FMI 17 | Rail pressure sensor: signal offset out of tolerance |
| FMI 3 | Fuel rail pressure sensor circuit fault - Voltage above allowed. Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 4 | Fuel rail pressure sensor circuit fault - Voltage below allowed. Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 15 | Fuel rail pressure sensor circuit fault - Signal value above the maximum allowed. Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 17 | Fuel rail pressure sensor circuit fault - Signal value below the minimum allowed. Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 0 | Selector cylinder sensor drifts from its position. Repair: Switch the ignition off, switch it on again and repeat the test. If the fault persists, replace the control unit. |
| FMI 3 | Rail pressure sensor voltage above the upper limit. Scan tool code: P0193. Effect: Engine speed is limited. |
| FMI 4 | Rail pressure sensor voltage below the lower limit. Scan tool code: P0192. Effect: Engine speed is limited to 1400 rpm. |
| FMI 7 | Engine failed to start: no pressure built up in the rail. Scan tool code: P016E. Effect: Power limited, the engine runs unevenly. |
| FMI 15 | Rail pressure sensor drift: voltage too high. Scan tool code: P0191. Effect: Engine speed is limited. |
| FMI 16 | Rail pressure correction value at the maximum limit. Scan tool code: P0190. Effect: Power limited, the engine runs unevenly. |
| FMI 17 | Rail pressure sensor drift: voltage too high. Scan tool code: P0191. Effect: Engine speed is limited. |
| FMI 18 | Rail pressure correction value at the minimum limit. Scan tool code: P0190. Effect: Power limited, the engine runs unevenly. |
| FMI 22 | Positive rail pressure deviation during cold start and rapid heat-up. Scan tool code: P016E. Effect: Power limited, the engine runs unevenly. |
| FMI 23 | Negative rail pressure deviation during cold start and rapid heat-up. Scan tool code: P016E. Effect: Power limited, the engine runs unevenly. |
| FMI 27 | Zero delivery not reached at the lower set value limit of the metering unit governor. Scan tool code: P016E. Effect: Power limited, the engine runs unevenly. |
| FMI 28 | Zero delivery not reached at the lower set value limit of the metering unit governor. Scan tool code: P016E. Effect: Power limited, the engine runs unevenly. |
| FMI 3 | Fuel rail pressure sensor circuit fault (Voltage above allowable limit). Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 4 | Fuel rail pressure sensor circuit fault (Voltage below allowable limit). Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 15 | Fuel rail pressure sensor circuit fault (Signal value above maximum allowable limit). Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
| FMI 17 | Fuel rail pressure sensor circuit fault (Signal value below minimum allowable limit). Blink code: 1-3-3. Power will be reduced. Repair: Check the rail pressure sensor and its wiring. |
ZF AS-Tronic uses its own fault numbering: the number in the table below is an internal ZF code, not a J1939 SPN. It matches the title of this page by digit only and means something different.
| FMI 0 | Main gear engagement sensor signal stays in the selected position. |
Safe to drive. Below — how much time you have and what happens if you keep going.
Fuel is not arriving in the right amount or at the right pressure. It shows up first on climbs and under load.
You will most likely stall out on the road, and may not restart on the shoulder. A clogged filter or water in the tank you can nurse to a shop; a failing injection pump you cannot.
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.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Check the fuel filter and water trap, drain the water. In cold weather, suspect fuel waxing.
If the value really did go out of range, rather than a sensor circuit being broken, these normally light up after it:
They are not fixed separately — they go out together with this one. The list is deliberately short: only the links the reference is sure about.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.