30FFhigh severityPowertrain
Boost Pressure Control Deviation - Pressure Too Low
on 2021 BMW i3 Range Extender · RWD
What this code means
The turbocharger boost pressure is below the commanded setpoint and cannot reach target (OBD P0299). The ECU detects underboost, often triggering reduced power mode.
Symptoms
- Loss of power
- Limp mode
- Check engine light
Common causes
- Boost/charge air leak
- Faulty wastegate or actuator
- Faulty boost pressure sensor
- Turbocharger wear or failure
Diagnostic steps
- Read boost actual vs target values
- Inspect charge pipes for leaks
- Test wastegate actuator operation
- Check boost pressure sensor and turbo
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