DTC codes / U06xx · Network communication / U0687
U0687 is a network communication code indicating that a control module has lost contact with the catalyst temperature sensor for bank 2, sensor 2, which is the post-catalyst sensor on the bank opposite cylinder one. The module monitoring that sensor stops receiving valid data over the vehicle's communication bus, so it sets this code and may substitute a default temperature value or disable certain monitoring functions.
Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.
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