This bulletin applies to 2000-2019 Buick vehicles equipped with a gasoline engine. The SES light may be on.
Initial diagnosis may reveal any of the following fuel trim and/or O2 sensor related codes: P0101, P0137, P0138, P0140, P0141, P0157, P0158, P0160, P0161, P0171, P0174, P0420, P0430, P1174, P1175, P2096. P2097, P2098, P2099, P2177, P2178, P2179, P2180, P2187, P2188, P2189. P2190, P2270, P2271, P2272 and/or P2273.
If normal diagnosis does not lead to a resolution, and an intake vacuum leak or an exhaust leak is suspected, the use of J41413-200 Evaporative System Tester smoke machine or the J-41416 ultrasonic leak tester (or possibly using soapy water and low air pressure into the tailpipe) may be useful.
