- Oxygen, Lambda Sensor
- Exhaust Oxygen Sensor (O2 Sensor)
- Measures oxygen in the exhaust so the ECU can correct the air-fuel mixture
- NTK "1721" - Not available
AUDI - A4, A3, A6, A5, TT; BMW - 3, 5; SEAT - Ibiza, Cordoba; SKODA - Fabia, Roomster; VW - Polo; ALFA ROMEO - 156, Spider