Oxygen sensor my check engine light went on, so I had it diagnosed at my local autozone. They told me it was the oxygen sensors. I bought them but haven't replaced them just yet. Now my truck trembles when im stopped, or parked, and jerks when I turn it on and put it in drive or reverse. Is it the oxygen sensors or is there more to it? Is there a special procedure in replacing the oxygen sensor? I'm not an expert, and just learning about cars.

Both of those codes typicall refer to bad or disfunctional Oxygen Sensors. Take your car to AutoZone and they will hook upo their diagnostic tool to your car and diagnose the problem for FREE.

Hi, no, they are not related. The oxygen sensor(s) are part of the ignition/emissions sytem and help regulate fuel flow/mixture. The A/C system is self contained and does not affect other engine systems. Mike

Unfortunately, this is a common problem with the Fords. The only way to be certain, is to take it to your local auto repair shop or AutoZone and have it diagnosed with a computer. AutoZone will do it free of charge. If the vehicle is still running properly, it is usually something like an oxygen sensor in the exhaust, and at $125 each for the 5 of them, it is usually not worth dealing with. Just have to learn to live with the dash light being on. Good luck!

Hi

The trouble areas associated with this code are as follows:
1)Gas leakage on exhaust system
2)Oxygen sensor
3)Heated oxygen sensor
4)Three–way catalytic converter

The idea is to check for exhaust leaks first then the front sensor and rear sensor. If these all check out then the cat needs to be replaced.

Hope this helps. Thanks for using fixYa

Some auto parts stores (like AutoZone) will diagnose the code for the check engine light for free. If the vehicle is running fine it may be something as simple as a bad oxygen sensor.

Had a similar issue where I would press the gas and not get a response or very little response. You could have a multitude of issues, but if the check engine light is on and it's driving ok, I would say it might be a sensor issue, oxygen sensor, fuel pressure sensor or MAP sensor. My problem was the rear oxygen sensor and the part was $219. The fuel pressure sensor was also replaced ($189 for parts) and the MAP sensor ($150 for parts). First thing you should do though is get the download of diagnostic codes from the check engine light being on and then further diagnose from there. Not sure where you are, but if you want to do yourself Autozone or Advance Auto can do that for free. That will tell you where you should focus your effort next.

code p 0138 refers to 2 items
1--heated oxygen sensor(HO2S) 2 bank 1--high voltage ==causes --wiring short to positive --HO2S---ECM
2--oxygen sensor (O2S) 2 bank 1--high voltage ===causes wiring short to positive ---ECM
code p 0139 refers to 2 items
1--- heated oxygen sensor (HO2S) 2 bank 1--slow response ===causes --heating inoperative --wiring--ECM
2--oxygen sensor (o2S) 2 bank 1 slow response ===causes --wiring --- O2S

heated oxygen sensors9HO2S) are in the exhaust manifold before the cat converter
Oxygen sensors (O2S) are after the cat converter
it is indicated that the HO2S is faulty-
check the wiring and /or replace both sensors

That code is for the 02 sensor down by the catalytic converter, that one should be changed.

Causes A code P0420 may mean that one or more of the following has happened:

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Retarded spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings

Robert

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Autozone oxygen sensors do not function properly in Toyota vehicles. Just had a Tacoma yesterday with the same issue. New sensors, runs poor, check engine light on. Toyota sensors fixed it right now.