OBD-II code · Network
U0643 Lost Communication With Turbocharger/Supercharger A Temperature Sensor
The vehicle bus reports loss of communication with smart turbocharger A temperature sensor. Turbo overheat protection switches to a model-based estimate.
Is it safe to drive with U0643?
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
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Turbo A Temp Sensor, Vehicle Bus Wiring
Related codes
- U0689Lost Communication With Turbocharger/Supercharger B Temperature Sensor
- U0640Lost Communication With EVAP Fuel Vapor Temperature Sensor Circuit
- U0641Lost Communication With EVAP System Pressure Sensor/Switch Circuit A
- U0642Lost Communication With EVAP System Pressure Sensor/Switch Circuit B
- U0644Lost Communication With Wastegate Position Sensor A
- U0645Lost Communication With Active Air Dam Module
- U0646Lost Communication With Motor Electronics Coolant Pump A
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.