Safe to driveUntil the next service
SPN 523420 is a manufacturer number outside the standard J1939 table: different makes can put different things under it. Below — how it is worded by KAMAZ, MAZ and YaMZ, and what the second half of the code (FMI) means.
| FMI 2 | Watchdog CY310 ↔ controller: implausible operation |
| FMI 2 | ECU watchdog timer error - Counter error, ECU must shut down. Blink code: 2-6-4. The engine will not start. Power will be reduced. Repair: Contact a service centre. |
| FMI 2 | ECU watchdog timer fault (Counter error, ECU must shut down). Blink code: 2-6-4. The engine will not start. Power will be reduced. Repair: Contact a service centre. |
| SPN 523420 FMI 2523420/2 · 523420.2 | data erratic or intermittent |
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.