Mercedes GLE Hybrid Crankcase Ventilation Issue

The symptoms you describe align with a potential crankcase ventilation valve issue. The valve regulates pressure within the crankcase and redirects blow-by gases back into the intake manifold for combustion, reducing emissions. A malfunction can disrupt this process, leading to increased crankcase pressure, forcing oil past seals, resulting in smoke, reduced performance, and the check engine light. What diagnostic work did you perform? What diagnostic codes were retrieved from the ECU?

The diagnostic code retrieved was P052E, indicating a problem with the crankcase ventilation valve control circuit. Is this confirmation enough, or are there further tests to perform before replacing the valve?

The P052E code strongly indicates an issue with the crankcase ventilation valve or its control circuit. Visually inspect the valve and its associated hoses for any signs of physical damage, such as cracks or blockages. Given your symptoms and the corroborating diagnostic code, replacement of the valve is reasonable. It would still be advisable to seek assistance from a qualified technician to ensure correct installation and to rule out any underlying issues that may have contributed to the valve's malfunction.

I followed your suggestion and consulted a workshop. The crankcase ventilation valve was defective and replaced. The total repair cost was 360€. The car is now running smoothly, and the check engine light is off. I appreciate your help in diagnosing this issue.