Safe to driveUntil the next service
SPN 4042 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by International, Knorr-Bremse EBS and MAN, and what the second half of the code (FMI) means.
InternationalKnorr-Bremse EBSMAN
| FMI 2 | Trailer Auxiliary Power Switch — Trailer Auxiliary Power Switch Error |
| FMI 8 | Central control unit, EEPROM checksum error ESP config. Wrong signal |
| FMI 8 | Central control unit EEPROM ESP own configuration - Wrong signal |
| SPN 4042 FMI 24042/2 · 4042.2 | data erratic or intermittent |
| SPN 4042 FMI 84042/8 · 4042.8 | abnormal frequency or pulse width |
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.