Those codes are pre-cat O2 sensors for both banks.
Overrun means closed throttle while coasting. DME shuts off fuel under these conditions and O2 sensor output should be near zero. You may have leaking fuel injector(s) or oil blowby getting into the exhaust that O2 sensor sees. Use live data on a ODB2 scanner and look at O2 sensor voltage while coasting.
Too much air might cause this also. Does throttle close completely? Any vacuum leaks between TB and cylinder head?
The 50i's are massive oil consumers. How much oil does yours use?
https://bmwfault.codes
10-28-2023, 10:38 AM
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