This only applies to the four-cylinder engines. On various long-stroke, six-cylinder engines with an underbody filter (i.e., a DPF that is not coated with a catalyst), it has always been located on the engine side, at the entrance to the center tunnel.
I've already replaced one on a four-cylinder engine before. What I found interesting was that the dealership had it in stock, and the temporary parts specialist knew the part number by heart on a Friday afternoon at 3:30 PM, and pulled it from the warehouse without having to look for it

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