engine light came on.

[s4houston]

My engine light has been on for the past couple weeks now. I had it check out at autozone and the code came up as PO1136 and PO1138. The technician said the code read as malfuction fan and oxygen sensor. What fan? What oxygen sensor. I mean my car only has 60k miles. Is it commond for a car to have a bad o2 at this mileage? I'm not convince, so what I did I removed the battery cable and have it wait for a few min to reset the computer then installed it back. Whola, the light goes off but only off for a few day then went back on again. Is it safe to do this because I am tired of reset the date/time and the stereo code every time I disconnect the battery. I really want to turn off the light completely by replace the o2 but which one? The diag. machine doesn't say which bay ( front or rear/ left or right) there are 4.... o2 in the car. Does anyone have this problem and if so how do you solve it. How do you know which oxygen sensor is bad. How do you test them? If you know which code is which (PO1136, PO1138?). Thank you for all your answer and please no smart a** comment. We all here to help each other out and share our knowledge.

[DannyDeez]

If you have a warranty then take it to the dealership. They just replaced one of my O2 sensors at about 70,000 miles. My check engine light came on as well. I dont know which one it was, they were able to tell though.

[TXCOS4]

Also o2 sensors are replaced no matter if you have warranty or not if the car is under 80k miles. Its for all cars, some law i think

[batmannie]

mine was on too. but then it went away. or maybe it just burnt out? lol

[Kaotic]

O2 sensor typically don't outright die. They tend to flicker before completely dying. What happens is that the CE light comes on in cycles based on the the fault check everytime you turn the ignition. If you reset it, it'd take a couple of ignition cycles before your car is convinced something's amiss and throw the CE light. 60k to have bad O2 is very common. FYI, you can buy the identical VW O2 sensor for like $20, as opposed to the audi version for $120, or something ridiculous like that. You just have to keep your old O2 harness and splice it with the VW harness. (Depending on which one you're replacing, you may have to use the old O2 wires too since VW may not be long enough. Number of wires is the same. Go figure. Same damn thing, and audi can make +100$ profit just cuz it's an audi, and people will pay it. BTW, if O2 is bad, engine may think the cat converter is bad too, even though it's fine. If the front O2s are bad, engine will run rich, gas milage will go down, which will eventually foul your cat. You have 4 O2s, 2 front (one for each cylinder bank) and 2 in the back. Engine uses the front ones for feedback in closed loop.