It is possible that the air conditioning systems in the vehicles mentioned above may generate a humming noise during operation.
To fix this problem, check the part number on the air conditioning system's control device. If a 32-bit control device is installed, the vehicle manufacturer provides a modified software. If a 16-bit control device is installed, it must be replaced with a 32-bit control device and upgraded with a new software version.
Part numbers of the affected 32-bit control devices:
13 581 999 / 13 581 998 / 13 581 131 / 13 581 132 /
13 578 953 / 13 578 954
Part numbers of the affected 16-bit control devices:
13 578 112 / 13 578 113 / 13 344 280 / 13 344 281 /
13 577 783 / 13 577 784
Part numbers of the 32-bit replacement controllers:
13 581 998 (for vehicles with air conditioning systems with 2 zones)
13 581 999 (for vehicles with manual air conditioning systems)
Important safety note
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