I have a GMC Sierra 1500 2017 4.3L v6 engine. I’ve been having an issue when decreasing the speed... when I decrease the speed I feel a big jolt. To me I believe it might be an issue with the transmission but I’m not sure & I only have 57000km so I don’t understand why I would have this issue. And yesterday I had an engine light come on. I read the code and it showed the code “P015B”. I went to look up what it means and I got this...“When an OBD-II equipped vehicle has a stored P015B code, it means that the powertrain control module (PCM) has detected a delayed response time from the upstream (first one after the exhaust leaves the engine, in front of catalytic converter) oxygen (O2) sensor or circuit for engine bank one.”... can anyone explain what this means? And if this has anything to do with transmission.
