U0674Lost Communication With Wastegate Position Sensor B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Electric wastegate actuators need position feedback so the controller can hold the turbine bypass at the commanded opening. On twin-turbo engines the second charger gets its own sensor, and U0674 says the digital frames from that sensor B have stopped or are corrupt. GM uses the sibling U0644 for wastegate A over SENT (25OBDG03B, Type A), yet none of the GM tables lists U0674. Ford's 2024 gasoline summary goes the analog way for charger B: P2ABB below 0.50 V or P2ABC above 4.50 V within 4 s, and a position error beyond 20 mm sets P25B5/P25B6. So no published source uses U0674 itself. CARB counts wastegate valve position among the diesel data items. Expect boost on that charger to be reduced or the wastegate held open.
- What you may notice
- Check engine light
- Reduced power, boost limited on one charger
- Sluggish response under load
- Likely causes
- LikelyWiring to the wastegate B actuator heat-damaged or chafed
- PossibleActuator connector loose or corroded
- PossiblePosition sensor inside the actuator failed
- RareWeak supply voltage or poor ground
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.