2 front oxygen sensors broke at the same time?



Did you see any OBDII codes? Have you used any chemicals in the gas tank or sprayed into the air intake?
My c240 has 129000 miles on it. I did not use anything unless they pour something into my tankin the last maintenance service. I did not check my battery for the last 3 years. Maybe I should do it first? Thank you again and waiting your advices.



