OBD-II code · Network
U0656 Lost Communication With Turbocharger/Supercharger Boost Control A Position Sensor
The vehicle bus reports loss of communication with smart boost control A position sensor (electric wastegate / VTG actuator position). Closed-loop boost control loses its actual feedback.
Is it safe to drive with U0656?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Boost Control A Position Sensor, Vehicle Bus Wiring
Related codes
- U02B0Lost Communication With Turbocharger/Supercharger Boost Control B Position Sensor
- U0653Lost Communication With EGR Sensor C
- U0654Lost Communication With Diesel Intake Air Flow A Position Sensor
- U0655Lost Communication With Diesel Intake Air Flow B Position Sensor
- U0657Lost Communication With Turbocharger/Supercharger Bypass Valve A Position Sensor
- U0658Lost Communication With Windshield Temperature Sensor
- U0659Lost Communication With Left Front Temperature Actuator
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.