Do not driveTo the nearest safe stop
J1939 code SPN 609. Below — how the fault is worded at the factory by Knorr-Bremse EBS, MAN, Mercedes-Benz and Renault Trucks, and what the second half of the code (FMI) means in the standard.
Knorr-Bremse EBSMANMercedes-BenzRenault Trucks
| FMI 0 | Central control unit in controller. Undefined fault |
| FMI 0 | Central control unit - Undefined fault |
| FMI 16 | Internal temperature of CPC4 too high |
| FMI 2 | EECU internal fault. Repair: Replace the EECU control unit. |
| FMI 3 | EECU internal fault. Repair: Replace the EECU control unit. |
| FMI 6 | EECU internal fault. Repair: Replace the EECU control unit. |
| FMI 8 | EECU internal fault. Repair: Replace the EECU control unit. |
Do not drive. Stop as soon as it’s safe to do so — don’t keep going.
The code is flagged critical: the manufacturer considers it unsafe to keep driving without checking.
This code alone cannot say what will fail next, so stop at the first safe opportunity and look at it on the spot.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.