The O2 sensor should not be replaced unless it's causing problems. If Cal vehicle, you would a check engine light, however the best way is to have some one check the on/off ratio, basically make sure it's in closed loop. If it is, don't even worry about the thing.


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Mercedes-Benz Master Guild - 2 years
Shop Foreman - 20 + years - dealer.
Part owner - MBZ Transmission remanufacture
2000 SL500
1995 E320
1989 300SE