Pls I have this code in my Honda Accord 1999, 4 cyl, Auto transmission, ULEV

Got this code after CEL came on while driving and it said it's air fuel ratio sensor malfunction.

Some people told me they are the same and so interchangeable, while some said they are not interchangeable.

I'm confused. My fuel economy is halved already.

Any experience/ideas/suggestions

azat:
Pls I have this code in my Honda Accord 1999, 4 cyl, Auto transmission, ULEV

Got this code after CEL came on while driving and it said it's air fuel ratio sensor malfunction.

Some people told me they are the same and so interchangeable, while some said they are not interchangeable.

I'm confused. My fuel economy is halved already.

Any experience/ideas/suggestions

P1166 in Honda accord means ''A/F sensor Heater circuit malfunction''.
AF sensor is the same thing as O2 sensor 1 whose primary function is fuel management .
P1166 may either refers to a faulty AF sensor or fault along the AF connector circuit to the PCM.
Check the AF connector circuit first before the AF sensor itself for fault.
Definitely ,malfunction of AF sensor will cause your car to run rich .

Air/ Fuel Sensor is the same as Oxygen sensor but being the before the CATALYST it monitors the Ratio of Fuel to Air that goes into the Cylinders and you know in the Air present is the Oxgen which supports combustion. There for your faulty sensor or a problem along the circuit to this sensor prompted the 2 fault code. Check if the sensor is connected before replacing it.

honmusa:


P1166 in Honda accord means ''A/F sensor Heater circuit malfunction''.
AF sensor is the same thing as O2 sensor 1 whose primary function is fuel management .
P1166 may either refers to a faulty AF sensor or fault along the AF connector circuit to the PCM.
Check the AF connector circuit first before the AF sensor itself for fault.
Definitely ,malfunction of AF sensor will cause your car to run rich .

thank you. I have checked the wires, mo visible faults. So I can replace with the regular Honda oxygen sensors I was shown in the market?

See the sensor type n location

azat:
thank you. I have checked the wires, mo visible faults. So I can replace with the regular Honda oxygen sensors I was shown in the market?

Dear Azat, an A/F sensor also known as Heated Air Fuel ratio sensor is NOT same thing with an O2 sensor. I repeat. It is NOT same thing with O2 sensor. Although their work might be similar which is measuring Air Fuel stoichiometry, telling the ECU to run the engine rich or thing, the distinguishing factor between them is that while an O2 sensor just measures the fuel trim, the A(F sensor is a wide band sensor and it has a heater core to heat up the stream of waste gases out of the out-take pipes before the catalyst. This way, it ACCURATELY measure the fuel trim, then tells the ECU to run the engine either rich or thin so as to get the engine to its optimal operating temperature to get fuel efficiency.


You CANNOT swap an O2 sensor for an A/F sensor and vice versa.

Your AF sensor has a part number. Use that part number to purchase a new or a certified working used one. Besides, they might look similar, but they have some differences. Those sensors are very sensitive and over tightening them could damage them.

lomomike:


Dear Azat, an A/F sensor also known as Heated Air Fuel ratio sensor is NOT same thing with an O2 sensor. I repeat. It is NOT same thing with O2 sensor. Although their work might be similar which is measuring Air Fuel stoichiometry, telling the ECU to run the engine rich or thing, the distinguishing factor between them is that while an O2 sensor just measures the fuel trim, the A(F sensor is a wide band sensor and it has a heater core to heat up the stream of waste gases out of the out-take pipes before the catalyst. This way, it ACCURATELY measure the fuel trim, then tells the ECU to run the engine either rich or thin so as to get the engine to its optimal operating temperature to get fuel efficiency.


You CANNOT swap an O2 sensor for an A/F sensor and vice versa.

Your AF sensor has a part number. Use that part number to purchase a new or a certified working used one. Besides, they might look similar, but they have some differences. Those sensors are very sensitive and over tightening them could damage them.

For this model of car ,AF sensor is still the same narrow band o2 sensor.

honmusa:

For this model of car ,AF sensor is still the same narrow band o2 sensor.

Bro, no manufacturer is daft to label an AF sensor same as O2 sensor. Let the OP detatch the upper sensor and the lower sensor, snap their picture and also post their part number for all to see. If it is O2 sensors, the manufacturer won't say it is A/F sensors.

@ Azat, did the car have 4 of these sensor or 2 or only 1?

Did the sensor come before or after the catalytic converter?

Pls snap a picture.

azat:
thank you. I have checked the wires, mo visible faults. So I can replace with the regular Honda oxygen sensors I was shown in the market?

@ Azat, you said your car was scanned... Pls post the code(s) here lets determine if its an O2 or AF faulty sensor.

azat:
thank you. I have checked the wires, mo visible faults. So I can replace with the regular Honda oxygen sensors I was shown in the market?

U cannot replace with anyhow honda o2 sensor.u need to use the part number on ur faulty o2 sensor to guide u in selection .I will advice u against buying tokunbo ,source for new ones cos they are very delicate device and difficult to test.. bad ones atimes don't trigger MIL.

lomomike:



Bro, no manufacturer is daft to label an AF sensor same as O2 sensor. Let the OP detatch the upper sensor and the lower sensor, snap their picture and also post their part number for all to see. If it is O2 sensors, the manufacturer won't say it is A/F sensors.

@ Azat, did the car have 4 of these sensor or 2 or only 1?

Did the sensor come before or after the catalytic converter?

Pls snap a picture.

Most manufacturer in their datasheet use the term AF(Air Fuel Ratio sensor) for O2 sensor 1 and CMS(Catalyst Monitoring Sensor ) for O2 sensor 2
AF sensor can be categorized into two Narrow band and Waveband band .Both look similar in construction but the distinctive factor is the stoichiometric voltages .
The stoic voltage for Narrowband is 450mv while for Wide band 3.3v .Check up http://www.enginebasics.com/EFI%20Tuning/AF%20Ratio%20Basics.html
http://en.wikipedia.org/wiki/AFR_sensor
so the way the op can determine which one he has is to run a live data on the AF sensor to determine the stoic voltage.
The image below is for the Honda accord 99 AF sensor (o2 sensor 1)

honmusa:

Most manufacturer in their datasheet use the term AF(Air Fuel Ratio sensor) for O2 sensor 1 and CMS(Catalyst Monitoring Sensor ) for O2 sensor 2
AF sensor can be categorized into two Narrow band and Waveband band .Both look similar in construction but the distinctive factor is the stoichiometric voltages .
The stoic voltage for Narrowband is 450mv while for Wide band 3.3v .Check up http://www.enginebasics.com/EFI%20Tuning/AF%20Ratio%20Basics.html
http://en.wikipedia.org/wiki/AFR_sensor
so the way the op can determine which one he has is to run a live data on the AF sensor to determine the stoic voltage.
The image below is for the Honda accord 99 AF sensor (o2 sensor 1)

Assuming youre using a denso to replace,

Denso 234-902 5 Air Fuel Ratio Sensor
Denso 234-462 1 Oxygen Sensor


Miss any of those part numbers, you will get workdone=zero.

Previously, O2 sensors were used, but if your vehicle has upstream and downstream sensor, the upstream is an AF sensor.
Except i am using a toyota explanation then but...
Messrs Piyke, Gazzuzz, Siena abeg come explain.

lomomike:


Dear Azat, an A/F sensor also known as Heated Air Fuel ratio sensor is NOT same thing with an O2 sensor. I repeat. It is NOT same thing with O2 sensor. Although their work might be similar which is measuring Air Fuel stoichiometry, telling the ECU to run the engine rich or thing, the distinguishing factor between them is that while an O2 sensor just measures the fuel trim, the A(F sensor is a wide band sensor and it has a heater core to heat up the stream of waste gases out of the out-take pipes before the catalyst. This way, it ACCURATELY measure the fuel trim, then tells the ECU to run the engine either rich or thin so as to get the engine to its optimal operating temperature to get fuel efficiency.


You CANNOT swap an O2 sensor for an A/F sensor and vice versa.

Your AF sensor has a part number. Use that part number to purchase a new or a certified working used one. Besides, they might look similar, but they have some differences. Those sensors are very sensitive and over tightening them could damage them.

Thanks lomomike

TUDEXautoCARE:
See the sensor type n location

thanks

lomomike:



Bro, no manufacturer is daft to label an AF sensor same as O2 sensor. Let the OP detatch the upper sensor and the lower sensor, snap their picture and also post their part number for all to see. If it is O2 sensors, the manufacturer won't say it is A/F sensors.

@ Azat, did the car have 4 of these sensor or 2 or only 1?

Did the sensor come before or after the catalytic converter?

Pls snap a picture.

In the whole of the service manual, only the sensor on the exhaust manifold that was labelled as A/F sensor. It is usually labelled as "A/F sensor/Primary heated O2 Sensor ", depending on the car engine type. It has 4 wires to it. It is precatalytic

Cant snap my car now, but this internet pic below is exactly as it is in my car. And the engine type written is exactly as mine: F23A4 ULEV

Also information on the code in the service manual, as well as a diagram representing the sensor

honmusa:

U cannot replace with anyhow honda o2 sensor.u need to use the part number on ur faulty o2 sensor to guide u in selection .I will advice u against buying tokunbo ,source for new ones cos they are very delicate device and difficult to test.. bad ones atimes don't trigger MIL.

Thanks bro.

Please where can I locate the part number of the sensor? Where can I purchase a new sensor in Nigeria?

azat:
Pls I have this code in my Honda Accord 1999, 4 cyl, Auto transmission, ULEV

Got this code after CEL came on while driving and it said it's air fuel ratio sensor malfunction.

Some people told me they are the same and so interchangeable, while some said they are not interchangeable.

I'm confused. My fuel economy is halved already.

Any experience/ideas/suggestions

lomomike:

Assuming youre using a denso to replace,
Denso 234-902 5 Air Fuel Ratio Sensor
Denso 234-462 1 Oxygen Sensor
Miss any of those part numbers, you will get workdone=zero.
Previously, O2 sensors were used, but if your vehicle has upstream and downstream sensor, the upstream is an AF sensor.
Except i am using a toyota explanation then but...
Messrs Piyke, Gazzuzz, Siena abeg come explain.

Please pay close attention to the part numbers posted by Lomomike for the AF sensor. If not the disco light will remain illuminated. Gosh! I hate that light!
Your vehicle is ULEV designed to meet stricter California emission standards as such it uses a more expensive AF sensor compared to non-ULEV models. I do not know if you can find the new part here, you may need to look abroad.

azat:
Please where can I locate the part number of the sensor? Where can I purchase a new sensor in Nigeria?

Its inscribed on the metallic body side after the screwing portion.

The death of all these sensors signifies that u need a new engine.Its always hard to secure those sensors so pls my frnd plan on buying new engine

azat:
Please where can I locate the part number of the sensor? Where can I purchase a new sensor in Nigeria?

Check the body very well for a combination of numerals and letters scribbled on it.
Call @ 08061166316 , I can help u to arrange

Piyke:




Please pay close attention to the part numbers posted by Lomomike for the AF sensor. If not the disco light will remain illuminated. Gosh! I hate that light!
Your vehicle is ULEV designed to meet stricter California emission standards as such it uses a more expensive AF sensor compared to non-ULEV models. I do not know if you can find the new part here, you may need to look abroad.

Thanks very much.

lomomike:


Its inscribed on the metallic body side after the screwing portion.

Ok, will check. Thanks

honmusa:

Check the body very well for a combination of numerals and letters scribbled on it.
Call @ 08061166316 , I can help u to arrange

ok. Will call you later.

NnamdiChidi:
The death of all these sensors signifies that u need a new engine.Its always hard to secure those sensors so pls my frnd plan on buying new engine

Oga titus, you try o!

NnamdiChidi:
The death of all these sensors signifies that u need a new engine.Its always hard to secure those sensors so pls my frnd plan on buying new engine

Totally wrong!

hummmmmmmmn▪ @ Lomomike , Mr Too know. Thank God for Google and brighter grammmer. Someone like you would have been driving your students A Y. We will like u to copmlete your explanation on why the pre-Cat sensor of the upstream is referred to A/F ratio sensor and why the After Cat is the Oxygen sensor
n
. A/F sensor/ Primary heated Oxygen sensor.
Explain. Dont confuse a lame Man

TUDEXautoCARE:
hummmmmmmmn▪ @ Lomomike , Mr Too know. Thank God for Google and brighter grammmer. Someone like you would have been driving your students A Y. We will like u to copmlete your explanation on why the pre-Cat sensor of the upstream is referred to A/F ratio sensor and why the After Cat is the Oxygen sensor
n
. A/F sensor/ Primary heated Oxygen sensor.
Explain. Dont confuse a lame Man

So it has gotten to this level that you now take pleasure in insults and name calling? Is it frustration or injured pride or what? What has brighter grammar got to do with the explanations I've given in this topic?

Mind you I am not a mechanic, I don't run a workshop, but I have touched more lives and brought smiles to faces of car owners via my 'little knowledge of cars' I don't know about you. But the whole write ups you've been giving in this thread about AF sensors and O2 sensors speaks volume on your level of competence shows you're a Kazeem. Also, your resolve to a personal attack and name calling shows the level of your immaturity.
Thank God for DIY guys like Piyke who have replaced such said sensor before and knows their workings.

Better close that worksop, go back take extensive classes and practical lessons on car repairs and maintenance, buy books, subscribe to latest development.

azat:
In the whole of the service manual, only the sensor on the exhaust manifold that was labelled as A/F sensor. It is usually labelled as "A/F sensor/Primary heated O2 Sensor ", depending on the car engine type. It has 4 wires to it. It is precatalytic

A/F sensors are pre-cat sensors, or Upstream sensors. Meaning they are installed between the bolt on side and the catalytic converter on the header.
But O2 sensors are installed after the catalytic converter.



What it does it simply to use a heated element inside to run a test via an electric pulse up to 8amps to test the stream of exhaust gases before they get to the cat. This system is made to know the exact amount of waste gases (Carbon Monoxide) and un burnt fuel. It then signals the ECU to adjust the STFT and LTFT to either run rich or thin. This gives the whole emission system a SLEV or ULEV class to conform to strict California emission standards. This sensor is a wide-band sensor

An Oxygen Sensor only test to detect presence of unburnt fuel. If your car have only O2 sensor its a LEV class vehicle. This sensor is a narrow band sensor.

Both Oxygen sensor and A/F sensor looks alike and have 4 wires in your car but they're different to a trained or experienced eye.

Since you use a honda with AF sensor, check the rear window, you'll see ULEV pasted on it except its been tampered with. Your car is a California emission compliant vehicle.


Please mr tudexautocare, read more

http://www.aa1car.com/library/wraf.htm

https://answers.yahoo.com/question/index?qid=20090409084109AASROGT

And stop kazeemizing peoples car with your 1968 datsun knowledge.

lomomike:




A/F sensors are pre-cat sensors, or Upstream sensors. Meaning they are installed between the bolt on side and the catalytic converter on the header.
But O2 sensors are installed after the catalytic converter.



What it does it simply to use a heated element inside to run a test via an electric pulse up to 8amps to test the stream of exhaust gases before they get to the cat. This system is made to know the exact amount of waste gases (Carbon Monoxide) and un burnt fuel. It then signals the ECU to adjust the STFT and LTFT to either run rich or thin. This gives the whole emission system a SLEV or ULEV class to conform to strict California emission standards. This sensor is a wide-band sensor

An Oxygen Sensor only test to detect presence of unburnt fuel. If your car have only O2 sensor its a LEV class vehicle. This sensor is a narrow band sensor.

Both Oxygen sensor and A/F sensor looks alike and have 4 wires in your car but they're different to a trained or experienced eye.

Since you use a honda with AF sensor, check the rear window, you'll see ULEV pasted on it except its been tampered with. Your car is a California emission compliant vehicle.


Please mr tudexautocare, read more

http://www.aa1car.com/library/wraf.htm

https://answers.yahoo.com/question/index?qid=20090409084109AASROGT

And stop kazeemizing peoples car with your 1968 datsun knowledge.

Thanks lomomike. You are correct.

See my sensor here. The number on it is 100. Does it mean I should look for one with the same 100 inscribed? Thanks

Good morning house,i scanned my car Toyota Rav4 98 and this code came up; P0141 02 Sensor heater circuit Bank 1 sensor 2.Plz how do i fix the codes.Thanks