Fendt 0F.2.0F – A038 - ECU, Central Electrical System: Trailer socket, terminal 54 faulty. X018 - Rear socket.

The tractor's central electrical system has detected an electrical fault (such as a short circuit, open circuit, or excessive resistance) on Terminal 54 of the rear trailer socket (designated as component X018). Terminal 54 is the designated circuit for the brake lights / stop lamps.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• FENDT 300 Vario (COM III & SCR Phase 3b)
• FENDT 400 Vario (COM III)
• FENDT 500 Vario SCR (Phase 3b)
• FENDT 700 Vario (COM III & SCR)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III & SCR)

1. 1

   Isolate the trailer by disconnecting it from the tractor. If the fault code goes away, the short or open circuit is in the implement's brake light wiring, not the tractor.

2. 2

   Visually inspect the rear trailer socket (X018) for physical damage, heavy corrosion, dirt, or water ingress that could cause bridging or shorting between pins.

3. 3

   Trace the wiring harness from the X018 rear socket back toward the A038 Central Electrical ECU. Look for pinched wires, chafing against the chassis, or melted insulation.

4. 4

   Use a multimeter to test Terminal 54 (brake light pin) on the socket for continuity to the ECU and check for a short to ground. Verify if voltage is present when the brake pedal is depressed.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent accidental shorts during repair.

2. 2

   Clean or Replace the Socket

   If the X018 socket is simply dirty, spray it thoroughly with electrical contact cleaner and use a small brush to remove debris. If the socket is heavily corroded or physically broken, unbolt it from the rear mounting bracket. Disconnect the wires, noting their pin locations, and wire in a new replacement socket. Ensure the brake light wire is firmly secured to Terminal 54.

3. 3

   Repair Harness

   If chafed wiring was found during the diagnostic phase, cut out the damaged section and splice in new wire using waterproof, heat-shrink butt connectors to prevent future moisture ingress.

4. 4

   Test

   Reconnect the battery. Use a multimeter or a 12V test light on Terminal 54 of the rear socket while an assistant presses the brake pedal to confirm proper voltage delivery.

5. 5

   Clear Codes

   Clear the stored 0F.2.0F fault code from the tractor's memory using the Fendt terminal or FENDIAS diagnostic software.