Safe to driveUntil the next service
SPN 520394 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by SITRAK and Volvo, and what the second half of the code (FMI) means.
| FMI 2 | SMU hardware monitoring module: alarm group 6, failure 20. Scan tool code: P3139. Effect: Torque limited, the engine may shut down. |
| FMI 9 | LCM (MID216) is not receiving signals from the instrument panel control unit (MID140) over the SAE J1939 data link. Open or partially damaged data link wiring between the units. |
| SPN 520394 FMI 2520394/2 · 520394.2 | data erratic or intermittent |
| SPN 520394 FMI 9520394/9 · 520394.9 | 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.