2009 Mercedes-Benz P0174: What It Means & Is It Safe to Drive?
P0174 on the 2009 Mercedes-Benz: System Too Lean (Bank 2). 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
Same as P0171 but for bank 2. The engine is running too lean on the side that contains cylinder 2.
Common causes on the 2009 Mercedes-Benz
- Vacuum leaks affecting bank 2
- Faulty MAF or O2 sensor
- Fuel delivery issues
Symptoms
- Check Engine Light
- Rough idle, hesitation
- May appear with P0171 on V6/V8 engines
Typical fixes
- Smoke test for vacuum leaks
- Inspect intake gaskets and hoses
- Check fuel pressure and filter
Repair cost range
For a 2009 Mercedes-Benz, repairs for P0174 typically fall between $100 and $600, depending on the root cause and labor rates in your area.
Known issues on Mercedes-Benz
Mercedes M272 V6 P0174 Bank 2 lean is often a failed MAF sensor or a vacuum leak at an intake manifold gasket. The M272's plastic intake manifold can crack near cylinder head mating surfaces. Inspect the intake manifold thoroughly with a smoke machine before condemning the MAF.
Most commonly affected models
E350 M272 2006–2012ML350 M272 2006–2011C300 M272 2007–2012