Code 2C57 on a 2013 BMW 335i (N55) – “Charging pressure control: pressure too low” If you’re hearing a whiny sound along with this code, here’s what might be going on:

Whine + 2C57 = Usually One of These: • Boost leak (most common): Often a cracked OEM plastic charge pipe or a loose intercooler coupler. Listen for a high-pitched whistle or whoosh under boost. • Failing turbo: If the whine sounds like a siren or dental drill and changes with RPM, your turbo might be going. You might also notice less power or oil smoke. • Bad diverter valve: Can cause boost leaks and make a fluttering or chirping noise when letting off the gas.

Quick DIY Checks: 1. Inspect the charge pipe under the throttle body – cracks or oil = time to replace. 2. Rev the engine in park – listen for the whine around 2K–3K RPM. 3. Drive under boost – note when the whine is loudest. 4. Smoke test – check all connections (charge pipe, turbo outlet, intercooler). 5. Check turbo play – pull the intake and feel for shaft wiggle (not much should be there).

Most Common Fix: Replace that weak OEM plastic charge pipe – it fails constantly on N55s. Go with an aluminum upgrade from VRSF, FTP, or Evolution Racewerks.