Safe to driveEnough to reach the yard
J1939 code SPN 74. Below — how the fault is worded at the factory by ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.
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 6 | Short circuit to positive supply on main air valve Y10 output. |
| SPN 74 FMI 674/6 · 74.6 | current above normal or grounded circuit |
Safe to drive. Below — how much time you have and what happens if you keep going.
This is not the fault, it is the reaction to it: the ECU is cutting power to protect the engine or the aftertreatment.
The limit will keep tightening until the cause is fixed. The code to chase is the one that triggered this, not this one.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.