Oxygen Sensor – Before Catalyst – BMW E65 E66 E67 730i – 2005-2008 – 0258017098

Replace your failing oxygen sensor — also called an O2 sensor or lambda probe — on the BMW (2005–2008) with this OEM-spec direct fit. Matching part numbers 11787558055, 755805502, 0258017098, 11787586693 and 11787557758.

Common signs of failure

A failing lambda or oxygen sensor will turn on the check engine light and commonly log fault codes in the P0130–P0167 range (sensor circuit and heater faults). Drivers typically notice a sudden drop in fuel economy, rough or fluctuating idle, hesitation under load, a sulphur or rotten-egg smell from the exhaust, and in many cases an MOT emissions failure. On modern diesels and direct-injection petrols, a stuck or slow-responding sensor can also push the engine into limp mode.

Fitment notes

Plug-and-play installation with the correct factory connector — no diagnostic coding required. Most engines run a pre-cat (upstream) and a post-cat (downstream) sensor; cross-check your existing part number and the position on the exhaust to make sure you're ordering the right one. Apply a smear of anti-seize compound on the threads before fitting and torque to manufacturer spec. Standard 5 wire connector. Position: Front.

Frequently asked questions

How do I know if my lambda sensor is faulty?

An OBD2 scan showing P0130-series codes plus poor fuel economy is the clearest sign. Live data showing the sensor stuck at a flat voltage (instead of oscillating between roughly 0.1V and 0.9V) confirms a faulty sensor.

Pre-cat or post-cat — which one do I need?

Pre-cat sensors (upstream of the catalytic converter) control the fuel mixture. Post-cat sensors (downstream) monitor catalyst efficiency. Match the OEM number on your old sensor to the numbers listed above to be sure.

Will a new sensor fix my fuel economy?

If the original sensor is biased lean or rich, a correct replacement typically restores MPG within a tank or two of fuel. Drive at least 20-30 miles after fitting to allow the ECU to re-learn.