2015 Mercedes-Benz P0172: What It Means & Is It Safe to Drive?
P0172 on the 2015 Mercedes-Benz: System Too Rich (Bank 1). Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
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What this code means
Too much fuel relative to air. O2 sensor detects low oxygen in exhaust; PCM is reducing fuel trim.
Common causes on the 2015 Mercedes-Benz
- Faulty MAF or O2 sensor
- Leaking fuel injector(s)
- High fuel pressure
- Faulty purge valve stuck open
Symptoms
- Check Engine Light
- Rich smell, black smoke
- Poor fuel economy
- Rough idle possible
Typical fixes
- Replace MAF or O2 sensor
- Test fuel pressure and injectors
- Replace purge valve if stuck open
Repair cost range
For a 2015 Mercedes-Benz, repairs for P0172 typically fall between $100 and $600, depending on the root cause and labor rates in your area.
Known issues on Mercedes-Benz
Mercedes M271 turbo P0172 rich Bank 1 often comes from a stuck-open EVAP purge valve or a leaking fuel injector. On the M271 turbocharged engine, a boost leak causing ECU over-fueling can also trigger P0172—check the charge pipe connections and intercooler hoses.
Most commonly affected models
C250 M271 Turbo 2012–2015E250 M271 2011–2013