Lambda sensor for a VW Transporter T4 2.5 petrol engine

Catalytic converter lambda sensor for a VOLKSWAGEN Transporter T4:
- 2.5 petrol engine 115hp (AET) Advice: to determine whether your vehicle's excess pollution comes from the lambda sensor(s), have your vehicle diagnosed by your garage (OBD scanner).
Mechatechnic will not accept returned sensors showing signs they have been fitted. Thank you for your understanding.