Post-Cat Oxygen Sensor, Bosch - E39 540i/M5, E38 740i/iL (11781742051)
540/740: 1996-1998. Genuine Bosch O2 sensor to keep your emissions system running smoothly
E39 540i 97-98, E38 740i/740iL 96-98 post-cat O2 sensor (after the catalytic converter).
This the oxygen sensor (O2 or Lambda probe) located after the catalytic converter. It reads and checks the status of the exhaust after going through the catalytic converter. The engine computer uses this data to verify the cats are working properly. A failed O2 sensor can set several different types of fault codes so it's a good place to start if you have O2 sensor or heater circuit faults. Most cat manufacturers will insist that you have new post-cat O2 sensors when you install new cats. This is a new OEM O2 sensor from Bosch, the inventors of the system and the original supplier to BMW. This part number fits either bank 1 or bank 2.
E39 (97-03) > 540i
E39 (97-03) > M5 (00-03)
E38 (95-01) > 740i
E38 (95-01) > 740iL
E38 (95-01) > 750iL