CLAAS Id771Ah / 771Ah (97 16) – ENG (A15): Presence of water detected in the fuel

When this condition is detected by the water-in-fuel sensor, the system triggers a protective degraded mode, automatically reducing engine power to 50% to prevent damage to the high-pressure fuel injection system.

• Axion 810
• Axion 850
• Arion 510
• Arion 610
• Arion 630
• Arion 640

1. 1

   Visually inspect the decanter prefilter (fuel/water separator bowl) to confirm if water has accumulated at the bottom of the filter housing.

2. 2

   If no water is present in the fuel, inspect the water-in-fuel sensor (B381) and its wiring harness for continuity, short circuits, or open circuits to rule out a false trigger.

1. 1

   Locate the decanter prefilter

   Locate the decanter prefilter (fuel/water separator) on the engine.

2. 2

   Open the drain valve

   Open the drain valve at the bottom of the decanter prefilter to empty the accumulated water and contaminants.

3. 3

   Close the drain valve

   Close the drain valve securely once pure diesel fuel begins to flow.

4. 4

   Restart the tractor

   Restart the tractor. The engine ECU will clear the 50% power derate and the tractor will return to normal operating mode as soon as the error disappears from the sensor reading.

5. 5

   Replace parts if code persists

   If the code persists after draining, the fuel filter/water separator element or the water-in-fuel sensor itself may need to be replaced.