Details of error
Level 016 is not defined in chart of depreciation ZU01
Message No. AC689
Diagnosis Multi-level method 016 is not defined for chart of depreciation ZU01
Procedure Define multi-level method 016 in FI-AA Customizing.
The system is telling you that Multi-level method "016" is not defined in your chart of depreciation ZU01. A multi-level method is part of depreciation key configuration. It defines how depreciation is calculated over time (e.g., percentages, years, declining balance → straight line).
If a depreciation key refers to a multi-level method that is missing, you’ll get this error.
Solution:
SPRO → Financial Accounting (New) → Asset Accounting → Depreciation → Valuation Methods → Depreciation Key → Calculation Methods → Maintain Multi-level Methods
T-CODE : AFAMS
Step 1 : Enter Your Chart of Depreciation

Look for multi-level method 016.
If it doesn’t exist, copy from a standard method (e.g., from chart of depreciation 0A or 0US).
Again following the same Steps ,
SPRO → Financial Accounting (New) → Asset Accounting → Depreciation → Valuation Methods → Depreciation Key → Calculation Methods → Maintain Multi-level Methods
Step 1 : Enter the Chart of Depreciation (Standard Chart of depreciation e.g., from chart of depreciation 0A, 0IN or 0US).

Look for multi-level method 016.
Select this
Click on Copy Method
Enter Source and Target Chart of Depreciation

Then Click On save
Now You can Enter Depreciation Key LINR to Asset Master data .
Thanks,
Rita Jha