DTC B1686-88: Vehicle Speed Sensor Fault - CAN Signal: General Description
WARNING: This page is about a different car, the 2021 Kia Soul. However, it is still accessible from the selected car via links, so may be relevant.
The A/C control module detects ambient temperature only when the vehicle is driven. To determine whether vehicle is being driven, the A/C control module receives vehicle speed signal from ABS/ESP control module through the CAN signal.