Fendt 1.2.27 – OVERALL SYSTEM/TRACTOR: G001 - Battery 1 (12 VDC) - Short circuit to battery or earth

The system has detected a 'Short circuit to battery or earth' (ground) on the Battery 1 circuit. The primary symptom of this fault is that a 'Start not possible' condition is triggered, preventing the tractor from turning over or running.

• 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 400 Vario COM III
• FENDT 700 Vario COM III
• FENDT 800 Vario COM III
• FENDT 900 Vario COM III

1. 1

   Inspect the main battery (Battery 1 / G001) terminals, cables, and the main wiring harness leading to the starter and basic control unit for signs of chafing, melting, or exposed copper.

2. 2

   Use a multimeter to verify the battery is outputting a healthy 12 VDC.

3. 3

   Perform a continuity test on the positive battery cable to the chassis ground to confirm if a hard short to earth is present.

4. 4

   Check the starter lockout relay (K008) for a short circuit, which can sometimes be related or throw a concurrent 1.2.2C code.

1. 1

   Disconnect Power

   Disconnect the negative terminal of Battery 1, followed by the positive terminal, to safely isolate the electrical system.

2. 2

   Trace and Repair Wiring

   Trace the main battery cables. If a short to earth is found (e.g., a rubbed-through wire touching the tractor frame), repair the wire using heavy-duty heat shrink and electrical tape, or replace the damaged battery cable section entirely.

3. 3

   Battery Replacement (If Internally Shorted)

   If the wiring is intact but the battery itself has an internal short circuit, remove the battery hold-downs and replace the 12V battery.

4. 4

   Clean and Reconnect

   Clean the battery terminals and cable clamps with a wire brush. Reconnect the positive terminal first, then the negative terminal, ensuring they are tightened to spec.

5. 5

   Clear Codes

   Connect the Fendt SERDIA diagnostic tool to the tractor's diagnostic port. Read the codes and use the 'delete error' function to clear code 1.2.27 (and any associated codes like 00B6, 00B7, 00BA, 00BC).

6. 6

   Test

   Attempt to start the tractor to verify the 'Start not possible' condition has been resolved.