Wires look good, and the 18 fuse is good. Should I replce the 02 sensor? Duh, right? How to replace the 02 sensor? Engire light just came on yesterday. Read the code using a code reader. The car is running like normal, maybe using a little more gas than normal in the last few days.
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2003 Ford Focus Question: Car has P0135 02 Heater Circuit Bank 1 Sensor 1 code.
Answer #1Justin Case Automotive Repair, Inc. (67 Answers) , Homosassa, FL - (352) 354-1008Justin Case Auto July 11, 2013, 05:44Technician
Test for battery voltage to the sensors heater circuit. If OK then ohm heater circuit. Should be 3-30 ohms. If it's not replace sensor.
To replace the sensor use an oxygen sensor socket and with a warm engine - not hot, not cold - remove sensor.
Keep in mind... I'm in Florida so I don't have rust issues like you might. You might be better off taking it to a shop incase it needs to be heated up to get out. You don't want to round off the sensor or strip the treads in the exhaust. That will get expensive to repair.
agree with justin