My engine light recently came on. A scan told me it was my bank one O2 sensor. I bought the part, but am unsure of exactly where the sensor is. Any help would be appreciated

Hello!! Im a proud owner of a 2014 Nissan Juke 1.5 DCI N-tec. Weel all have been fine since 2014, but 4 days ago, this check engine light came on. Went to the mechanic right away to diaghnose and had 3 issues. 1 - Canbus error 3 - Spark Error 3 - Diluted Oil Just add that the light that show...