Safe to driveUntil the next service
SPN 42 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by ZF AS-Tronic, and what the second half of the code (FMI) means.
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 10 | Loss of output signal to main air valve Y10. No air supply. |
| SPN 42 FMI 1042/10 · 42.10 | abnormal rate of change |
Safe to drive. Below — how much time you have and what happens if you keep going.
A standalone fault with no immediate consequences for driving.
Show the codes at the next service. If a second code from the same system appears, stop putting it off.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.