the O2 sensors are located before and after the primary catalytic converters. I don't know if bank 2 is the driver's or passengers side but I do think SENSOR 2 is the on after the convertor. A MAF sensor malfunction will trigger that error code. I found out the hard way. I replaced the sensor the error code suggested, cleared the error code and it kept coming up. replaced the MAF and the error code disappeared. kind of a toss up.
99CLK320-One day I woke up and my slab had morphed into a McLaren MP4-12C
INMotionusa Chip Tune, Sprintbooster,
VIPclk320's cold air ram intake and front & rear strut bars, Ghostrider's short tube headers and rear camber kit, MB front control arm camber bolts, Vogtland Springs, Bilstein Sport shocks, Goodridge stainless braided brake lines. Wish list: SuperSprint resonator and muffler, seconary cats deleted.