Fendt 1E.1.53 – Engine Control Unit (ECU) / EDC 7 / KHD engine control / Deutz engine control: B086 - Rail pressure sensor: Rail pressure outside setpoint range

The actual fuel pressure inside the high-pressure accumulator (common rail) does not match the pressure requested by the engine control unit. This triggers a critical error message stating that the engine will automatically shut down in approximately 4 to 5 minutes to prevent damage.

• 309 Vario COM III
• 310 Vario COM III
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• 922 Vario COM III
• 924 Vario COM III
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1. 1

   Read Live Data: Use the Fendt SERDIA (Service Diagnostics) program to read the measured values of the B086 sensor and compare actual rail pressure against target rail pressure using the 'Graphic readings' function.

2. 2

   Wiring and Circuit Check: Inspect the 3-pin connector and wiring harness for the B086 sensor for cable breaks or short circuits.

3. 3

   Mechanical Valve Check: Verify the mechanical high-pressure limiting valve on the rail to ensure it is not opening prematurely or failing to close.

4. 4

   Low-Pressure System Check: Ensure the low-pressure fuel system is supplying adequate fuel to the high-pressure pump (monitored by the B087 low fuel pressure sensor, which should read approx. 6 bar).

1. 1

   Turn off engine and wait

   Turn off the diesel engine. You MUST wait at least 30 seconds before starting any work on the fuel system to allow the extreme high pressure in the common rail to dissipate safely.

2. 2

   Locate sensor

   Locate the B086 Rail pressure sensor on the common rail (high-pressure accumulator).

3. 3

   Disconnect connector

   Disconnect the 3-pin electrical connector from the sensor.

4. 4

   Clean area

   Thoroughly clean the area around the sensor to prevent dirt from entering the open fuel rail.

5. 5

   Remove sensor

   Unscrew and remove the faulty B086 sensor.

6. 6

   Install new sensor

   Install the new rail pressure sensor and tighten it to the manufacturer's specified torque.

7. 7

   Reconnect harness

   Reconnect the electrical harness.

8. 8

   Connect diagnostic tool

   Connect the SERDIA diagnostic tool to the tractor.

9. 9

   Clear fault codes

   Clear the stored fault codes from the ECU memory (associated sub-codes for this fault include FC: 00D3, 00D4, 00D5, 00D6, 00D7, 00D8).

10. 10

    Verify repair

    Start the engine and verify that the 5-minute shutdown warning message no longer appears on the terminal.