Safe to driveEnough to reach the yard
J1939 code SPN 2791. Below — how the fault is worded at the factory by KAMAZ, MAZ, SITRAK and YaMZ, and what the second half of the code (FMI) means in the standard.
| FMI 2 | EGR actuator: short circuit / open circuit / overheating. K-line code on KamAZ-5490: MR2 16679. |
| FMI 3 | EGR actuator: short circuit / open circuit / overheating |
| FMI 4 | EGR actuator: short circuit / open circuit / overheating |
| FMI 5 | EGR actuator: short circuit / open circuit / overheating |
| FMI 0 | EGR valve position control error - Maximum positive deviation exceeded. Blink code: 6-8-1. Repair: Check all EGR system components and their wiring. |
| FMI 1 | EGR valve position control error - Maximum negative deviation exceeded. Blink code: 6-8-1. Repair: Check all EGR system components and their wiring. |
| FMI 2 | EGR control valve fault - Overheating. Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 3 | EGR control valve fault - CJ230 driver error. Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 4 | EGR control valve fault - Valve control current exceeded. Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 7 | EGR valve pneumatic actuator stuck - Bypass valve stuck. Blink code: 6-7-1. Repair: Check the pneumatic actuator of the EGR flap. |
| FMI 12 | EGR control valve fault - Current limited due to overheating. Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 2 | EGR valve command message error on the CAN bus. Scan tool code: P0403. Effect: Loss of communication with the modules, some functions are disabled. |
| FMI 3 | EGR valve power supply error. Scan tool code: P0403. Effect: Torque may be limited. |
| FMI 12 | System error in the EGR valve circuit. Scan tool code: P0403. Effect: Torque may be limited. |
| FMI 14 | EGR valve initialisation error. Scan tool code: P0400. Effect: Torque may be limited. |
| FMI 20 | High thermal load on the EGR valve powerstage in the ECU. Scan tool code: P0403. Effect: Torque limited, the engine may shut down. |
| FMI 21 | High temperature in the EGR valve control unit. Scan tool code: P040A. Effect: Fan and warm-up control may misbehave. |
| FMI 23 | EGR valve position deviation warning. Scan tool code: P0400. |
| FMI 24 | EGR valve position sensor error. Scan tool code: P0409. |
| FMI 0 | EGR valve position control fault (Maximum positive deviation exceeded). Blink code: 6-8-1. Repair: Check all EGR system components and their wiring. |
| FMI 1 | EGR valve position control fault (Maximum negative deviation exceeded). Blink code: 6-8-1. Repair: Check all EGR system components and their wiring. |
| FMI 2 | EGR valve control valve fault (Overheating). Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 3 | EGR valve control valve fault (CJ230 driver error). Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 4 | EGR valve control valve fault (Valve control current exceeded). Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
| FMI 7 | EGR valve pneumatic actuator seized (Bypass valve seized). Blink code: 6-7-1. Repair: Check the pneumatic actuator of the EGR flap. |
| FMI 12 | EGR valve control valve fault (Current limited due to overheating). Blink code: 6-6-2. Repair: Check the electropneumatic EGR flap control valve and its wiring. |
Safe to drive. Below — how much time you have and what happens if you keep going.
Boost is not reaching its target: turbo, intercooler or intake. The engine compensates with mixture and runs hotter than usual.
You will lose pull, burn more fuel and add overheating on long climbs. If you hear a whine or a whistle from the turbo, stop — the wheel is breaking up.
This is an electrical fault: an open, a short or a bad contact in the sensor circuit. The value it measures is most likely fine. You can drive. But until the circuit is repaired this system runs blind and cannot warn you about a real failure.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Inspect the air filter and charge-air hoses: leaks and cracks produce exactly these codes.
This code is often not the fault itself but a knock-on. If any of these is in the same readout, start with it:
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.