02 Sensors

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charbaby

charbaby

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I am having some difficulty deciding on which O2 Sensor to get for my daughter's '06 Mazda3 2.0L "DOWNSTREAM". This car has ~100K miles now! I am assuming that these are OE sensors but, IDK either!

When I look up the sensor(s), it may mention Cal(2 req; 4; 5)]
Some mention Fed Em; 5. Does this mean that I CAN'T buy this one? Buying only 1 and not 2...???

I want the exact fit as I don't want to splice wires together. I'd rather pay a bit more and get the exact length wire with the proper connections.

Also, what is the difference between the Denso or NTK $100 sensor(exact fit) compared to the Bosch or Beck/Arnley $400 sensor(exact fit)???

The pictures of the connections all look the same in Rock Auto or AdvAutoPts websites. These pics are supposed to be "Exact" to the application.

I want to buy Denso or NTK/NGK and I don't want to spend top dollar when lesser money will do!

This car is NOT California! It has 2 sensors(downstream and upstream) not the 3 required for Cal.
 
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Nothing wrong at all with Denso or NTK exact fit o2 sensors.
Shop around online for prices, RockAuto, Amazon, etc...
Just make sure you back check the part # with the catalogue of the company you choose.
 
I will only use the exact fit with the plug in. The NTK ones are really expensive. SO no doubt they are the correct fit for my cars.
lol.gif
For my wifes Lexus they are almost $500 on Rock Auto. Plus you have to drop the front half of the exhaust to get to them. The two AF ratio ones are right there on top. I'll leave the 02 sensors to the Toyo dealer as they have the techscan system to scan the whole car realtime and tell which sensor is lazy or fried. OR you can DIY and just change both downstream.

Either way I will only use what are the OEM ones.

BTW, my dealer charged me $179 for the same sensor that was $257 on Rock Auto. So, shop around.
 
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The Denso and NTK are actually the lesser expensive on Rock Auto and AAP(RA being cheaper than AAP). These are for the downstream sensors:

Denso part#234-4329
RA $$54.79 - AAP $93.99 - Amazon $29.00

NTK part #24446
RA $82.79 - AAP $128.99 - Amazon $77.00

Which is a better brand?

But, there are other brands costing between $235-$425. I don't get it
frown.gif
I may have these above prices off by a few dollars but, you see what I mean?
 
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Originally Posted By: Char Baby
The Denso and NTK are actually the lesser expensive on Rock Auto and AAP(RA being cheaper than AAP). These are for the downstream sensors:

Denso part#234-4329
RA $$54.79 - AAP $93.99

NTK part #24446
RA $82.79 - AAP $128.99

But, there are other brands costing between $235-$425. I don't get it
frown.gif
I may have these above prices off by a few dollars but, you see what I mean?

I haven't checked Amazon yet!


I totally know what you mean. That is why I made sure to find out which the manufacturer uses.
 
Both brands are mentioned as OE!

I see some brands mentioning Ceramic...Which is better, ceramic or something else?
 
Originally Posted By: Char Baby
Also, what is the difference between the Denso or NTK $100 sensor(exact fit) compared to the Bosch or Beck/Arnley $400 sensor(exact fit)???


IMHO if you buy the Denso or NTK it would be like paying $100 and receiving a part worth $100, while buying the Bosch would result in paying $400 and getting a $50 part.
 
When you say downstream, do you mean the ones after the cat converter? Just want to verify that first.

If so, are you replacing them just because they have 100k miles on them or are they throwing cat efficiency codes? If they are popping the CEL, just put in spacer bungs to get them farther out of the exhaust stream and save yourself the money. They don't control the A/F mixuture so they only function to determine the efficiency of the cat converter.
 
Originally Posted By: threeputtpar
When you say downstream, do you mean the ones after the cat converter? Just want to verify that first.

If so, are you replacing them just because they have 100k miles on them or are they throwing cat efficiency codes? If they are popping the CEL, just put in spacer bungs to get them farther out of the exhaust stream and save yourself the money. They don't control the A/F mixuture so they only function to determine the efficiency of the cat converter.


Yes, it's throwing a CEL and yes, its after the Cat. This one is in the cat that's under the floor(not under hood) about in line with the center consol. I will check this spacer bung. Can you elaborate further? Where can I obtain these bungs?
 
Originally Posted By: Char Baby
Originally Posted By: threeputtpar
When you say downstream, do you mean the ones after the cat converter? Just want to verify that first.

If so, are you replacing them just because they have 100k miles on them or are they throwing cat efficiency codes? If they are popping the CEL, just put in spacer bungs to get them farther out of the exhaust stream and save yourself the money. They don't control the A/F mixuture so they only function to determine the efficiency of the cat converter.


Yes, it's throwing a CEL and yes, its after the Cat. This one is in the cat that's under the floor(not under hood) about in line with the center consol. I will check this spacer bung. Can you elaborate further? Where can I obtain these bungs?


Companies that sell performance exhaust systems that delete the cat or replace it with a less effective cat often sell the O2S spacer.
 
I would be OK with using Bosch O2 sensors as well.

But in your case, I would make sure that you do not need a CA emissions part (although I would think that downstream Oz sensor would not be a CA emissions only part).
 
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You really need to post the code, you may have a bad converter and changing the downstream O2 sensor may not fix the problem. Catalyst Efficiency below threshold is normally set when the switching rate of the downstream sensor reaches a critical percentage of the upstream. It varies by vehicle and exhaust design but it should be less than 80% of the front. A good scan tool will show both sensors. If the downstream sensor basically follows the upstream, then the cat is failing. Check your exhaust system for leaks.
 
I'd only put a Denso in your car. Have read of way too many issues with the Bosch sensors, as of late. Spent a lot of time in Camry forums, and was swayed by the people who ended up replacing the Bosch sensors (thought they'd save a few dollars).
 
$25.00 OEXTRA Standard O2 sensor for my '96 Maxima, stamped NTK JAPAN 4ZD3, from Rockauto. Clearly this Standard sensor was made by NTK and an amazing value.

O2_zps7b0b2854.jpg


o21_zps57bb3ae2.jpg


o22_zps2fd98ec1.jpg
 
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Code#'s are P0145 & P0171

Converter is fine; no rot or broken welds and no exhaust noises anywhere. Everything is solid throughout the exhaust system.

I just think that the sensor has gotten lazy as I have reset the CEL and it takes some time for the CEL/codes to return.

This started around Easter weekend
 
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P0171 has NOTHING to do with the post catalytic sensor. It could be bad main O2 sensor or bad MAF. You need to check live readings of MAF sensor and O2 sensor to see which one is the bad one. Of course, you could have vacuum leaks which can generate P0171 if the freeze frame data says the code was generated at idle. If it was generated at load/high speed, then you need to look at the fuel delivery aka fuel pump or injectors.

And P0145 seems somewhat suspect given it means "P0145 O2 Sensor Circuit Slow Response Bank 1 Sensor 3" I am not aware of any vehicle having the "3rd" sensor! It is like the third half of the Cartalk show :-)
 
California models have 3 sensors(1-upstream, 2-mid, 3-downstream)
This car only has 2 sensors 1 & 3
As long as we have time, I'll make sure we're doing the right one.
 
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