Fendt 04.1.B2 – A050 - ECU, basic control unit: Fault in EPROM programming (travel range selector I/II)
Issue description
Memory (EPROM) within the basic control unit has a programming error, corruption, or data loss specifically affecting the parameters for the travel range selector. The travel range cannot be changed while driving.
Applies to these machines
11 machines- 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)
- Fendt 400 Vario (COM III)
- Fendt 700 Vario (COM III)
- Fendt 800 Vario (COM III, S4)
- Fendt 900 Vario (COM III, S4, Gen6)
Check the cause
Verify the fault by confirming that the tractor is locked out of changing travel ranges while driving
Scan for other A050-related codes (such as 04.1.B3 or 04.1.B5) which also indicate EPROM programming or checksum errors
If hardware failure is suspected, perform pin-out testing on the A050 ECU using the Fendt 160-pin adapter box (Tool No. X899.980.304.000) and adapter cable (Tool No. X899.980.304.201) to verify power, ground, and CAN bus integrity
Repair steps
Perform EOL programming
The official repair action for fault 04.1.B2 is to perform EOL (End-Of-Line) programming.
Connect diagnostic software
Connect the tractor to the FENDIAS dealer diagnostic software.
Reflash/reprogram the A050 Basic Control Unit
Reflash/reprogram the A050 Basic Control Unit with the correct EPROM parameters for the travel range selector.
Hardware Replacement (if programming fails)
If the ECU will not accept the EOL programming or the EPROM chip is physically damaged, the A050 unit must be removed.
Remove the A050 ECU
On models like the 900 Vario, the A050 ECU is located on the right mudguard behind a removable panel. Disconnect the battery, remove the panel, unplug the multi-pin connectors, and unbolt the module.
Install and program the new module
Install the new or repaired A050 module, and perform EOL programming to pair it with the tractor's immobilizer (A077) and engine control unit (A169).
Parts you might need
(7)Fendt Basic Control Unit (A050)
G737.970.070.035Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
G737.970.070.037Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
G835.970.070.014Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
G931.970.070.032Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
G931.970.070.033Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
G931.970.070.046Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
Fendt Basic Control Unit (A050)
R917006740Because the A050 controls highly specific tractor functions, a replacement unit must be programmed via FENDIAS to match the exact chassis and equipment level of the host tractor.
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