Q: Check Engine Light and code for O2 sensor

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The Check Engine Light is on. For a while it would go on and off, but now it is permanently on. We scanned the car and it listed the code for the O2 sensor. The car now stalls out when I turn it on. I have to rev the engine to pump fuel, and after I rev it a few times, it is good to go.

Hello. Knowing the actual code number would help determine the problem. If you are getting an O2 sensor code associated with the way it is running, then the sensor is more than likely bad. On this Toyota, the O2 sensor is actually an air/fuel mixture sensor that tells the computer how much fuel to put into the engine. If it is not functioning properly or if it is not heating correctly, then this will occur. I typically use a computer scan tool with live data to see what the sensor is reading. This is done when the problem is occurring to determine if it needs fixing. If you need further assistance, I recommend you have a mechanic, like one from YourMechanic, inspect for fault codes in the vehicle’s computer system and replace the oxygen sensor if it is said to be damaged.

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