OBD-II code · Network
U02AC Lost Communication With Turbocharger/Supercharger Boost Control A
The vehicle bus reports loss of communication with boost control module A (electric wastegate or VTG actuator). Boost pressure cannot be commanded; the engine reverts to a low-power fallback.
Is it safe to drive with U02AC?
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
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Boost Control Module A, Vehicle Bus Wiring
Related codes
- U02ADLost Communication With Turbocharger/Supercharger Boost Control B
- U02A9Lost Communication With Charge Air Cooler Coolant Pump A
- U02AALost Communication With Engine Disconnect Clutch
- U02ABLost Communication With Vehicle Thermal Management Control Module
- U02AELost Communication With Hybrid/EV Battery Coolant Pump
- U02AFLost Communication With Turbocharger Turbine Inlet Valve Position Sensor
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.