Check engine light is on, had checked, code is for oxygen sensor. but which one?

The second sensor for the catalytic efficiency just looks at what's coming through. If there were no codes for an oxygen sensor then the catalyst may be going. Not unheard of. If it's going bad the code will start coming back more frequent.

I found this online for you.
Possible causes for this check engine light code include:
Blown oxygen sensor fuse
Open circuit in oxygen sensor harness
Open circuit internal to oxygen sensor
Open circuit in PCM
Short circuit in oxygen sensor harness
Short circuit internal to oxygen sensor
Short circuit internal to PCM
Diagnostic Help: To diagnose a P0061 check engine light code we will need to test out the oxygen sensor wiring and also test the circuits through the oxygen sensor itself. The internal processor circuits are a possible cause but are much less likely, so the other areas are thoroughly tested first. See our article Automotive Circuit Testing 101, if you need more assistance with this. If concern is determined to be intermittent, check out our article on Intermittent Diagnosis and wiggle test connectors and wiring, attempting to duplicate concern. You may also use the "Get Help" link if you need specifications or have any other related questions. Remember to refer to an appropriate manual for specific instruction.

This code does not mean to replace the sensor , testing is what is suppose to happen .
P0131 O2 Sensor Circuit Low Voltage Bank 1 Sensor 1

Honda Civic P0131 02 Sensor Diagnosis

SAE J2012 Revised DEC2007 lists Diagnostic Test Code (DTC) P0133 as "O2 Sensor Circuit Slow Response Bank 1 Sensor 1"

This code basically means that the upstream oxygen sensor on bank one of your engine is not responding as quickly as it should to changes in oxygen leavels in the exhaust.

The usual causes of this is an oxygen sensor that is just plain worn out (if it has a lot of miles on it) or an oxygen sensor that is contaminated by engine oil or antifreeze leaks causing these fluids to be burned in the exhaust (like bad piston rings, defective PCV valve, blown head gasket, etc.).

In any case, the oxygen sensor needs to be replaced. However it should be noted that if it is caused by contamination like that described above, replacing it will only result in a new oxygen sensor doing the same thing if the cause of the contamination is not repaired.

The check engine light can come on for over 150 things, from a sensor to a loose gas cap, you will need to have the codes scanned, the computer stores codes when it detects something not working correctly,there are many auto part stores that will scan it for free and give you a print out of the codes, if you can give me the codes i could help you find out why the engine light is on, good day.

The code P0053 is for your Bank 1 Oxygen Sensor, the closest Oxygen Sensor to the engine, connected to the Exhaust. Replace your Oxygen Sensor, clear the code, and see if it comes back.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

I had this problem with my 05 Trailblazer and it happened around 50k miles. The oxygen sensor needs to be replaced and the part costs about 90 bucks but atleast you will have you're check engine light off.

This code can be set for either a short to ground, short to power, high resistance or open circuit on Oxygen Sensor for bank 2, (HO2S21). Bank 2 is on your right when standing at the front of the engine facing the crank, and this sensor is the first in line; before the converters. Check out our circuit testing article at www.engine-light-help.com/check-engine-light-circuit-testing.html for help with testing. From what I can tell the wires from that sensor are RED/WHT, WHT/RED, GRN, BRN. I would recommend checking related wiring for opens, shorts or chaffing before condemning the sensor. Just for info you may want to check out our article on Oxygen Sensors at http://www.engine-light-help.com/oxygen-sensor-codes.html Hope this helps.

P0041 Downstream Oxygen Sensors Swapped From Bank To Bank
How does a P0041 code trigger the check engine light? This code will trigger the light to come on under the following condition:

The Heated Oxygen Sensor Monitor, a strategy built into the computer, determines if the Heated Oxygen Sensor (HO2S) signal response for a change in fuel trim corresponds to the correct engine bank. If a response from the Oxygen Sensor being tested is not indicated, a trouble code will be set and the MIL (Malfunction Indicator Lamp) will illuminate.
Possible Causes:
Crossed Heated Oxygen Sensor harness connectors
Wiring swapped from one Oxygen Sensor connector to the other
Wiring changed at the computer connection or in the related harness

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