OK, I failed to mention the CEL came on briefly 2 or 3 times, but is not currently lit. Anyway, figuring the code would be stored in memory, took the car by Autozone where they hooked up the scanner and retrieved a bank 1 oxygen sensor code. A universal sensor was $60 (supposedly the wiring should match right up, but it has to be spliced on).

Question: which one is bank 1 oxygen sensor? Do I have to crawl under the car or is there access to it from somewhere in the cabin (i.e. under the carpet)?

Thanks!

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280