Code U0671 indicates that the vehicle's control module has lost communication with Fuel Temperature Sensor B. This is a network-related fault where the module is no longer receiving the expected data signal from the sensor.
The fuel temperature sensor B has suffered an internal electronic failure and cannot transmit data.
Broken, chafed, or shorted wires between the sensor and the control module.
Moisture or debris in the sensor connector causing a loss of electrical continuity.
A blown fuse in the circuit providing power to the sensor or its associated module.
Internal failure of the PCM/ECM preventing it from processing the sensor signal.
Yes, the vehicle will typically enter a 'limp home' or default mapping mode using preset temperature values, though efficiency may drop.
No. While the PCM is listed as a cause, U0671 is far more likely to be caused by a failed sensor or wiring fault. Replacing the PCM without first verifying the wiring and sensor is usually incorrect.
No, this is a data communication code for a temperature sensor and does not indicate a mechanical failure of the fuel pump.