The S500's "Check Engine" light came on so I dug out the trusty OBDII scanner. It came up with code P0136 "Sensor Circuit Malfunction (Bank 1, Sensor 2) and P0141 "Sensor Heater Malfunction (Bank 1, Sensor 2). I erased them, turned off the light and it came back on two weeks later--same codes. Incidentally, the car was being started from cold both times. Anyway, obviously an O2 sensor problem, correct? But which one? As I understand it, Bank 1 is a reference to whichever side of the engine cylinder one is located. But does Sensor 2 refer to the pre-cat or aft-cat sensor?
I have the same problem with my 97 E420. I need to find out which sensor to replace. Also I've had this problem over a year and the type of gas seems to effect how often the light comes on. Anybody else have tht coorolation?
Linear Mode
