Safe to driveUntil the next service
SPN 3985 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by International, and what the second half of the code (FMI) means.
| FMI 9 | Cab HVAC System Controller — HVAC Control Head Circuit Failed To Communicate With the Body Controller |
| SPN 3985 FMI 93985/9 · 3985.9 | abnormal update rate |
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.