This code indicates the engine control module is no longer receiving a valid signal from Barometric Pressure Sensor B. The engine computer uses barometric pressure data to adjust fuel and turbo boost calculations for altitude and weather conditions. A communication loss typically points to a wiring, connector, or sensor fault rather than a computer problem.
The sensor itself may have failed internally or be outputting an out-of-range signal the PCM cannot interpret as valid.
Chafed, corroded, or broken wiring between the sensor and PCM can interrupt the signal or reference voltage.
A loose, spread, corroded, or backed-out terminal at the sensor or PCM connector can cause intermittent or total signal loss.
The sensor may not be receiving proper 5-volt reference or ground from the PCM, preventing it from communicating.
A rare PCM communication driver failure or calibration issue could prevent the module from reading the sensor; this is uncommon and should only be considered after all other causes are eliminated.
Short distances may be possible, but reduced power, poor fuel mixture, and potential turbo control issues make extended driving inadvisable. Have it diagnosed promptly.
Usually not. Drivers are often told the PCM is bad, but the vast majority of U0680 cases are caused by the sensor, wiring, or connector. The PCM should be the last component tested, not the first.
Location varies by vehicle. Some integrate it into the PCM, while others mount a separate sensor on the intake, firewall, or body harness. Consult a model-specific wiring diagram for exact placement.
Not directly, but some vehicles share wiring or data logic between MAP and barometric sensors. A related code may appear alongside U0680 and should be investigated together.