Experiencing jerky rides and uncertain gear shifts in your Mercedes Benz B Class Automatic model can be unsettling. If you own a 2010 or similar W245 B-Class with a CVT gearbox and are encountering transmission issues, you’re not alone. Many owners report similar symptoms, often described as a “Transmission fault” warning appearing, accompanied by hesitant gear changes, especially at lower speeds.
The good news is that despite initial concerns, your B-Class is likely not in “limp mode,” but rather signaling a specific problem within its automatic transmission system. While it’s true that modern Mercedes vehicles, including the B-Class W245, are equipped with limp mode as a safety feature, the symptoms described point towards a more common culprit: the gearbox ECU.
This particular CVT gearbox in the Mercedes Benz B Class automatic models (and the W169 A-Class, sharing the same transmission) has a known design vulnerability. The Transmission Control Unit (ECU) is located inside the gearbox and encased in gel. Over time, the delicate wires within this ECU can break or become damaged, frequently disrupting the RPM signal. This intermittent connection confuses the ECU, leading to the erratic gear selection and jerky driving experience you’re noticing.
To properly diagnose the issue, it’s crucial to get the error codes read by a professional mechanic. This will help ascertain if the transmission ECU is indeed the source of the problem. If the error codes point to ECU issues, there’s a cost-effective solution. Instead of opting for a complete and expensive new CVT gearbox replacement, which dealerships might suggest, consider ECU repair. Specialist independent garages can often repair the transmission ECU for a significantly lower cost, potentially saving you thousands. Seeking out a Mercedes-Benz specialist familiar with W245 and W169 models and their common CVT issues is highly recommended for diagnosis and repair.
