Fendt 1.2.06 – Engine Control Unit (ECU) / EDC: Camshaft (B085) or Crankshaft (B088) Speed Sensor Defective or Out of Phase

The RPM signals from the camshaft and crankshaft are out of phase, or a sensor is defective or its signal is absent. This causes prolonged unsuccessful starting attempts (prolonged turnover) and rough engine running once started.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 820 Vario greentec COM III
• Fendt 900 Vario (COM III and S4 generations)
• Fendt Katana 85

1. 1

   Read extended fault codes using the Deutz SERDIA diagnostic program to confirm specific sub-faults (004B, 004C, 004D, 004E, 004F, or 0050)

2. 2

   Check the camshaft sensor (B085) wiring on the right side of the engine (flywheel housing) and inspect separation point X1678 for breaks or short circuits

3. 3

   Check the crankshaft sensor (B088) wiring on the front of the engine (crankshaft) and inspect separation point X1657

4. 4

   Use an oscilloscope or the SERDIA tool to verify if the sensors are supplying plausible speed curves and check if the double cog reference marks on the gears are damaged

1. 1

   Access the Sensors

   Depending on which sensor failed the diagnostic check, remove the necessary metal panels to access the right side of the engine/flywheel housing (for B085) or the front of the engine/crankshaft (for B088).

2. 2

   Disconnect the Battery

   Always disconnect the battery before replacing electronic engine control components.

3. 3

   Replace the Defective Sensor

   Disconnect the sensor at its separation point (X1678 or X1657). Unbolt the faulty sensor and install the replacement part.

4. 4

   Clear the Fault Codes

   Reconnect the battery. Connect the SERDIA diagnostic tool and delete the stored error codes (FC: 004B - 0050) from the EDC memory.

5. 5

   Test Run

   Start the tractor. Verify that the prolonged turnover is resolved and that the engine runs smoothly without rough idling.