Abstract: An exhaust monitoring sensor, such as an oxygen sensor, is used in an engine equipped with an exhaust system including first and second parallel pipes. The first and second pipes form respectively first and second exhaust passages through which exhaust gases can flow. A portion of the walls of the first pipe is common to a portion of the walls of the second pipe to form a partition wall separating the first and second exhaust passages. The partition wall has a hole extending therethrough. The sensor includes an exhaust-gas sampling tube extending from the first to the second exhaust passage through the hole. The tube has a bore, and first, second, and third openings. The bore communicates with the second exhaust passage via the second and third openings. The bore communicates with the first exhaust passage via the first opening. The sensor also includes an exhaust sensing section. At least part of the sensing section is located in the bore of the tube.