GF got a newer van about a month ago. She had an 05 T&C. Bought a 2013 Dodge Grand Caravan with 118 on it. Spent a whole day shopping different dealers and decided to go with the first one we looked at. It is super clean compared to every other one we looked at. Kind of a base model, no power opening doors, slider doors don't go down, back vent windows are manual. Does have the stow and go which she wanted. Need some help on it. Past couple of weeks we've been getting a random p0420 catalyst system efficiency below threshold bank 1. Where do I start? Haven't seen anything too helpful in online searches Replace o2 sensor bank 1 sensor 2? I can see sensor voltage with torque app, but the voltages bounce around so much it's hard to say.