Safe to driveTo the nearest safe stop
J1939 code SPN 231. Below — how the fault is worded at the factory by Meritor (ex-WABCO) and ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.
| FMI 5 | J1939 Communication — J1939 Data Bus Error |
| FMI 9 | J1939 Communication — J1939 Message Time Out |
| FMI 12 | J1939 Communication — J1939 Internal Error |
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 4 | CAN bus timeout: "EEC3". |
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.
Check the fuel filter and water trap, drain the water. In cold weather, suspect fuel waxing.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.