Fendt 08.1.17 – A024 - ECU, EPC B: ECU, EPC B; generator Ub+ > 18 Volt

The system has detected an overvoltage condition where the battery voltage (Ub+) supplied by the generator (alternator) exceeds 18 Volts. This is almost always caused by a failed voltage regulator inside the alternator, causing it to overcharge the electrical system. To protect sensitive electronics from overvoltage damage, the tractor automatically disables the rear electrohydraulic lifting gear control.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• Fendt 300 Vario COM III (309, 310, 311, 312)
• Fendt 400 Vario COM III
• Fendt 700 Vario COM III
• Fendt 800 Vario COM III
• Fendt 900 Vario COM III

1. 1

   Perform a live voltage test by measuring the voltage across the battery terminals with the engine running (should be 13.5V - 14.5V; readings near or above 18V indicate a failed voltage regulator).

2. 2

   Inspect the wiring harness from the G002 Alternator (Terminal B+ and D+) to the battery and ECU for damage or shorts to power.

3. 3

   Check the battery casing for swelling, venting, or acid leaks, as extreme overcharging can boil battery acid.

1. 1

   Disconnect Power

   Disconnect the negative (-) battery cable first, followed by the positive (+) cable to prevent accidental shorts and protect the ECUs.

2. 2

   Remove Electrical Connections

   Locate the G002 alternator on the right side of the engine. Disconnect the B+ (main power) and D+ (exciter/warning light) terminals.

3. 3

   Remove Drive Belt

   Relieve tension on the serpentine/drive belt using the appropriate tensioner tool and slip the belt off the alternator pulley.

4. 4

   Remove Alternator

   Unbolt the alternator mounting hardware and carefully remove the faulty unit from the engine bracket.

5. 5

   Install New Alternator

   Mount the replacement alternator and torque the mounting bolts to OEM specifications.

6. 6

   Reassemble

   Reinstall the drive belt, ensuring it is seated correctly on all pulleys. Reconnect the B+ and D+ electrical terminals.

7. 7

   Reconnect Battery

   Reconnect the positive (+) battery cable, followed by the negative (-) cable.

8. 8

   Verify Repair

   Start the tractor and measure the voltage at the battery. It should now hold steady around 14V.

9. 9

   Clear Codes

   Use the tractor's onboard terminal (Varioterminal) or a diagnostic tool to clear the inactive 08.1.17 fault code and verify that the rear EPC lifting gear functions have unlocked.