Fendt 0F.2.14 – A038 - Central Electrical System ECU: A038 - ECU, central electrical system (Left trailer socket, terminal 58 faulty)

This fault code indicates an electrical issue (open circuit, short to ground, or short to power) on the circuit supplying Terminal 58 at the rear trailer socket (X018), which provides power to the left-hand tail lights, side marker lights, and license plate lights of a connected implement or trailer.

• 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 / Stage 3b)
• Fendt 400 Vario (COM III)
• Fendt 500 Vario (SCR / Stage 3b, S4)
• Fendt 700 Vario (COM III, SCR, S4)
• Fendt 800 Vario (COM III, SCR, S4)
• Fendt 900 Vario (COM III, SCR, S4, Gen6)

1. 1

   Isolate the implement by disconnecting the trailer from the tractor's rear socket (X018) to see if the fault becomes inactive

2. 2

   Visually inspect the tractor's rear trailer socket (X018) for water ingress, packed dirt, or fertilizer corrosion

3. 3

   Turn on the tractor's parking lights and use a multimeter to test for 12V at Terminal 58 (Pin 7 on a standard 7-pin ISO 1724 socket)

4. 4

   Check the wiring harness for continuity or a short-to-ground between the X018 socket and the A038 Central Electrical System ECU

1. 1

   Power Down

   Turn off the tractor ignition and engage the battery disconnect switch before performing electrical repairs.

2. 2

   Address Implement Faults

   If the fault was isolated to the trailer, replace the blown left marker/tail bulb or repair the trailer's wiring harness.

3. 3

   Clean or Replace the Socket

   If the tractor's X018 socket is heavily corroded or physically broken, remove the mounting screws, pull the socket housing away from the bracket, and disconnect the wires. Clean the wire terminals with contact cleaner.

4. 4

   Install New Socket

   Wire the new socket according to the ISO standard (Terminal 58 / Black wire to Pin 7). Ensure the rubber weather boot is seated correctly to prevent future water ingress.

5. 5

   Repair Harness

   If the socket is fine but the harness is damaged (commonly rubbed through near the rear mudguard or axle housing), cut out the damaged section of the wire, splice in a new section, and seal it with marine-grade heat shrink.

6. 6

   Clear Codes

   Reconnect the battery, turn on the lights to verify operation, and clear the stored fault code via the tractor's dashboard terminal or the FENDIAS diagnostic tool.