SLK 200 (R171): P0130, P0171, and P0036 Codes Reappearing Despite Diagnostic Checks

Hello, Thank you for this website — it is by far the most accurate and comprehensive resource available for OBD-related information. My name is Jean-Christophe, and I own a 2005 SLK 200 (R170 model). Approximately three weeks ago, I began experiencing an issue with my vehicle: The first sign was the engine warning light illuminating on the dashboard. However, the car's overall performance remained unchanged. Upon further inspection using the OBD-II scanner, I consistently found that three fault codes appear together: P0130, P0171, and P0036. I took my vehicle to a Mercedes dealership, where they tested the lambda sensors and catalytic converter. Both components were confirmed as functioning properly. Despite these checks, the fault codes continue to reappear — even after being cleared from the system. Question: Could there be a single underlying cause triggering all three codes? For example, could a failure in the 'HO2S Heater Control Circuit' (P0036) lead to secondary issues such as 'O2 Sensor Circuit High Voltage' (P0138) and 'System Too Lean' (P0171)? Any insights or technical explanations would be greatly appreciated. Best regards, Jean-Christophe Denis