U0675 is a network communication diagnostic trouble code indicating the Powertrain Control Module (PCM) has lost communication with the turbocharger or supercharger speed sensor. This is typically caused by a wiring or connector issue rather than the sensor itself failing.
The wiring between the PCM and the turbo/supercharger speed sensor is damaged, chafed, or corroded, breaking the communication circuit.
Connectors at the sensor or PCM are loose, unplugged, or have oxidized/pitted pins causing intermittent or lost communication.
The turbocharger/supercharger speed sensor itself has failed internally and no longer transmits a signal to the PCM.
The sensor is not receiving proper reference voltage or ground, preventing it from communicating on the network.
Rarely, the PCM itself may have an internal fault affecting its ability to communicate with specific sensors. This is the least likely cause.
No. While some may suggest replacing the PCM, this is almost never the fix for U0675. The PCM rarely fails, and the cause is almost always wiring, connectors, or the sensor itself. Always diagnose the lower-cost possibilities first.
The vehicle may run in reduced power mode or the turbo/supercharger may not function properly. While not immediately dangerous, it should be diagnosed and repaired reasonably soon to avoid drivability issues and potential damage.
U0675 only applies to vehicles equipped with a turbocharger or supercharger that uses a speed sensor for boost control. It's more common on performance or forced-induction engines and may not appear on naturally aspirated vehicles.