The code indicates that the powertrain control module has lost communication with the wastegate position sensor B circuit. This sensor monitors the position of the turbocharger wastegate valve. When the signal is missing or invalid, the system stores U0674.
The sensor itself can develop an open circuit or internal failure, cutting off its signal to the PCM.
Broken wires, chafing, or a severed harness will prevent the sensor signal from reaching the module.
Moisture or oxidation at the connector can interrupt communication even if the sensor is functional.
A fault on the CAN or dedicated sensor bus that affects multiple modules may cause loss of this specific sensor signal.
A defective PCM can misinterpret or drop sensor inputs, but this is uncommon and usually accompanied by other control module codes.
Usually not; the most common cause is a faulty wastegate position sensor or a wiring/connector problem. PCM failure is rare and should only be considered after other checks.
The vehicle may enter a limp‑mode that limits boost pressure, so driving for an extended period can reduce performance and fuel efficiency. It is best to address the issue promptly.
Yes, because the turbocharger control is part of the emissions system; a stored code can cause a failed inspection until the fault is cleared.
If only the sensor or wiring needs replacement, the job can be completed in a few hours. Extensive wiring or PCM work may require more time depending on accessibility.