Exhaust Mercedes GLA-Class X156 (2014-2020)

Owners of Mercedes GLA-Class X156, especially diesel models like 200 CDI 4MATIC or 220 CDI, often face problems with the exhaust flap servomotor (part reference M16/57). This component, located after the DPF and catalytic converter in the exhaust line, controls the exhaust flap to create backpressure, improving torque and engine response. Over time, soot buildup, moisture, oxidation, and wear cause the servomotor to seize, leading to engine warning lights, limp mode (limited to 3000 rpm), acceleration stutters, and automatic transmission stuck in one gear.

At official dealerships, the half exhaust line is often replaced (costing between €650-1000 incl. VAT) because the servomotor is not sold separately. However, a more affordable solution is to purchase the genuine Mercedes servomotor alone, including screws and spring, from specialized suppliers. This can reduce costs significantly while maintaining original part quality.

Other reported issues include:

• Defective exhaust backpressure sensor, typically resolved by replacement at a mechanic.
• Failure of the exhaust flap motor, detectable through OBD diagnostics showing error codes.
• Abnormal noises such as clicking, vibration, or crackling, often due to poor exhaust assembly: misplaced retaining rings, missing rubbers, or loose bolts causing metal-to-metal contact.

These can usually be fixed by tightening linkages, adding felt padding, or correcting the assembly.

Use an OBD diagnostic tool to check for error codes related to the servomotor, backpressure sensor, or exhaust flap motor. Symptoms like limp mode, engine warning light, or acceleration issues often accompany faults in these parts. Pay attention to similar symptoms found in Mercedes Class A and CLA models, sharing the same platform as the GLA.

• Visual inspection beneath the vehicle to check the exhaust line status.
• Testing exhaust behavior at different engine temperatures.
• Observing for abnormal noises (>80 km/h or highway speeds).

Prioritize electronic diagnosis if issues persist after visual checks.

Krosfou provides high-quality, original-equipment-grade exhaust components manufactured in Europe. Our product range includes stainless steel catalytic converters and Diesel Particulate Filters (DPFs) certified by TÜV SÜD Automotive GmbH, ensuring superior quality and durability. We do not sell reconditioned parts, focusing instead on brand new, high-performance components that comply with manufacturer specifications and European regulations.

• Original parts designed for precise fit and performance.
• Manufactured with stainless steel INOX 409 and premium monoliths.
• Three-year warranty and free returns under specified conditions.

We support professional workshops and provide installation support, ensuring safe and reliable exhaust system maintenance.

When replacing exhaust system components such as catalytic converters or DPFs, please note the following:

Krosfou's warranty requires proper installation by a specialized garage, replacing all necessary gaskets, sensors, and injectors. Avoid starting the engine by pushing or towing and regularly maintain spark plugs and engine oil. Also, ensure:

• The vehicle reaches full operating temperature regularly for proper DPF regeneration.
• Replacement of associated catalytic converters upstream/downstream if applicable.
• Use of only copper connections if installing a connection before the catalytic converter.
• Vehicle must run on unleaded petrol when replacing catalytic converters and the Lambda sensor should be replaced after around 80,000–100,000 km.

Following these recommendations ensures optimum performance, longevity, and safety of your exhaust system.

While Krosfou focuses on original quality stainless steel exhaust components ensuring performance and compliance, some owners explore sport exhaust systems or valvetronic systems offered by specialized providers for enhanced sound and performance. However, such sport or tuning systems are not part of the Krosfou product range and should be chosen carefully considering your vehicle's specifications and warranty.

• Sport exhaust options exist for AMG and GLA 250 models.
• Valvetronic exhaust systems offer adjustable sound control via valves.
• Aftermarket choices often install stainless steel parts with improved flow and sport sound.

Always seek professional advice and check compatibility for your specific Mercedes GLA series when purchasing performance exhaust upgrades.

For thorough research and problem diagnosis, consider the following sources and strategies:

• Use OBD diagnostics to capture fault codes related to servomotor or sensors.
• Search online with keywords such as “Mercedes GLA servomotor exhaust failure,” “GLA 200 CDI exhaust noise,” or “GLA exhaust flap error OBD.”
• Visit forums and communities dedicated to Mercedes models for owner experiences and DIY fixes.
• Watch tutorial videos on replacing exhaust flaps or servomotors on platforms like YouTube.
• Consult professional garages with expertise in diesel and performance exhaust systems.

Krosfou also offers expert technical support and installation documentation for all original exhaust components, ensuring you receive the best possible service with our products.