Turbo coolant pump issue?

2018 BMW 330
98,000 MILES • AUTOMATIC
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BHAMDOC1
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Car had a leaking oil filter housing so replaced that and all is good, but keep getting drivetrain malfunction message without a check engine light. Replaced the small auxiliary pump same thing. Code keeps coming back 20a503. Car drives fine
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May 9, 2026 at 5:34 PM
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BHAMDOC1
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I read somewhere that once coolant system has been touched this is pretty much air in the system. I dont think these bleed like the previous generation which requires holding gas pedal 10 seconds and it does it on its own, can you find put how?
May 9, 2026 at 5:55 PM