P0175 on the 2024 Mercedes-Benz GLC (X254)
The P0175 code on your 2024 Mercedes-Benz GLC means the ECU has detected a rich air-fuel condition on bank 2. The 2024 GLC is powered by the M254 2.0-liter turbocharged four-cylinder with 48-volt mild hybrid technology, producing 258 horsepower in the GLC 300. Bank 2 refers to the rear pair of cylinders on this four-cylinder engine. The GLC is Mercedes-Benz's best-selling model worldwide, and its M254 engine represents the latest in the brand's four-cylinder technology.
Symptoms
- Yellow check engine light on the instrument panel
- Worsening fuel economy below rated figures
- Dark exhaust smoke
- Rough idle quality
- Fuel smell from exhaust
- Possible reduced performance
GLC SUV and M254 Engine
The second-generation X254 GLC shares its M254 engine with the C-Class and features the same advanced technology: direct injection at up to 350 bar, exhaust gas turbocharger with electric auxiliary compressor, 48-volt integrated starter-generator, and CAMTRONIC variable valve lift. The GLC's slightly higher ride height and SUV aerodynamics create marginally different engine load profiles compared to the C-Class sedan, but the P0175 diagnostic approach is essentially the same.
Causes on a New GLC
1. Defective Bank 2 Lambda Sensor
Manufacturing defects in the bank 2 wideband lambda sensor are the most common cause of P0175 on any new Mercedes-Benz. The sensor provides precise air-fuel ratio feedback, and any inaccuracy causes the ECU to add excess fuel to bank 2.
2. Fuel Injector Issue
The M254's ultra-high-pressure direct injection system demands perfect injector performance. A factory-defective injector that does not seal or atomize properly on bank 2 introduces unmetered fuel into the combustion chamber.
3. Electric Auxiliary Compressor Malfunction
The electric auxiliary compressor provides instant boost before the exhaust turbo spools. If it malfunctions, the air charge entering the engine during the transition from electric to exhaust boost can be inconsistent, creating conditions where the fuel map does not match actual cylinder filling.
4. CAMTRONIC Valve Lift Issue
CAMTRONIC adjusts intake valve lift to optimize efficiency at different engine speeds and loads. A fault on bank 2 can alter airflow into the rear cylinders, causing a combustion imbalance that pushes fuel trims past the P0175 threshold.
What You Should Do
- Contact your Mercedes-Benz dealer for warranty service
- Describe symptoms and when the check engine light appeared
- Do not attempt DIY repairs on a new vehicle
- Request a loaner vehicle during service
- Expect dealer to use XENTRY diagnostics for full ECU analysis
Warranty Information
The 2024 GLC is covered by Mercedes-Benz's 4-year/50,000-mile New Vehicle Limited Warranty. All P0175 diagnosis and repair costs are fully covered. The GLC's popularity means dealers are very familiar with the M254 engine and can typically diagnose and repair P0175 efficiently.
GLC Ownership Tips
Follow the Mercedes-Benz Service A and Service B schedules. Use approved MB 229.71 specification oil. High-quality fuel and regular maintenance keep the M254's complex fuel system and sensors operating correctly and reduce the likelihood of future fuel trim codes.