4 Series vs CLA-Class

The most frequently reported issue is electrical system malfunctions, with complaints logged for model years 2019, 2020, 2021, 2022, and 2025. The source does not itemize symptoms, but the category indicates faults in electrical components. Fire-related severity signals were also recorded for several years, making electrical problems a safety-relevant area to inspect.

Powertrain and engine complaints were reported for model years 2019, 2020, 2021, and 2022, with 12 complaints in 2019 and 10 in 2020. The source does not specify symptoms, but the category covers engine and transmission faults. It is recommended to have a specialist inspect for drivability problems, warning lights, fluid leaks, and repair history.

Service brake complaints were logged for model years 2023 and 2024, with 7 complaints in 2023 and 4 in 2024, plus hydraulic brake complaints in 2023. The source does not detail symptoms, but the category indicates brake system faults. Inspecting brake pedal feel, fluid level, lines, and warning messages is advised.

Affected years include 2021-2024 CLA 250, 250 4MATIC, and AMG 35/45 variants with the EQ Boost belt starter-generator. Watch for intermittent 48V electrical warnings, loss of mild-hybrid assist, rough start-stop behavior, and a generator warning light. The BSG belt pulley can detach and damage nearby parts, and the engine may fail to restart after auto stop-start. Inspect stored 48V fault codes and BSG belt condition on any used CLA.

Affected models include 2019-2023 CLA 250 and 2019-2023 AMG CLA 35/45 with the 7G-DCT or 8G-DCT. Look for harsh first-to-second gear engagement, clunking when slowing, delayed Reverse, and intermittent Transmission Malfunction messages. A documented TCU software update addressed shift quality, but without correction the mechatronic unit and clutch pack can wear prematurely. Ask the seller whether TSB LI-27.70-P-068727 was performed.

All 2020-2024 C118 CLA models with MBUX NTG 6.0 are affected. Symptoms include black-screen boot loops, Bluetooth drops, failed OTA updates, ghost touch, and an unresponsive touchscreen. Firmware updates reduced but did not fully solve the issue, and the H6 head unit sometimes must be replaced. Check the MBUX software version and whether any field service action or warranty repair has been completed.

Affected vehicles include 2019-2024 CLA 250 and AMG CLA 35/45, especially in winter-salt climates or with low annual mileage. Inspect the front discs for rust ridges, listen for squeal on light braking, and look for pedal vibration or judder after rain exposure. Low-metallic performance pads and disc corrosion cause premature noise and uneven pad transfer. The usual correction is disc and pad replacement per axle.

Affected cars include 2019-2024 C118 CLA models with the optional panoramic sunroof. Look for creaking or rattling from the roof frame over uneven pavement, damp headliner, or water in the footwells after heavy rain. Clogged drain tubes and failed headliner clips are the main causes, and advanced water intrusion can corrode electrical connectors under the seats. Clear the front drains and check roof panel alignment during inspection.

Affected vehicles use the M260 engine and include 2019-2022 CLA 250 models. Signs include long cranking, intermittent no-start, low-speed stalling, or a fuel smell. The fuel tank delivery module can fail and cut fuel pressure, causing sudden loss of power while driving. Check whether NHTSA recall 22V437 was performed and inspect for stored fuel-pressure codes before purchase.

Affected variants are 2020-2024 AMG CLA 45 and CLA 45 S with the M139 engine. Look for oil consumption around one liter every 1,500-2,000 km, blue smoke on cold start, and oil weeping around PCV or intercooler connections. The PCV system can fail, leading to turbo oil starvation, intercooler contamination, and catalyst damage. Ask for oil consumption history and whether updated PCV components were installed.