OBD-II code · Network
U0671 Lost Communication With Fuel Temperature Sensor B
The vehicle bus reports loss of communication with smart fuel temperature sensor B. Density and viscosity correction for injection quantity switches to a substitute value.
Is it safe to drive with U0671?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyBus wiring open or shorted
- PossibleModule without power or ground
- PossibleModule failed
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–1.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Fuel Temp Sensor B, Vehicle Bus Wiring
Related codes
- U0670Lost Communication With Fuel Temperature Sensor A
- U066ELost Communication With Charge Air Cooler Temperature Sensor Bank 2
- U066FLost Communication With Low Pressure Fuel System Sensor
- U0672Lost Communication With Engine Coolant Pump
- U0673Lost Communication With Ion Sense Module
- U0674Lost Communication With Wastegate Position Sensor B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.