Ecu Code 2 - Oxygen Sensor

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So yesterday I popped a code after driving for maybe 4-5 minutes. Things I noticed at the time were
A. Engine temp was at or near mid-point (close to or at normal operating temp)
B. Needle was below 'E' (I needed gas)
C. It had been raining and I was still kicking water around (I have a CAI, but I don't think I gobbled up any water or anything)
D. The engine didn't stutter or hesitate, nothing was out of the ordinary it just blinked on.

So I was only about a mile from a gas station, I filled up to the top with regular 87 of course. Since I shut off the car to fill up, the CEL went away. When I started back up and drove off I waited for it to reappear but it never did.

So today I pulled the code and got a '2', two short blinks. I waited for it to cycle back and double checked it. Yep, 2. So I look up here that 1 is oxygen sensor 'A', and 2 is oxygen sensor 'B'. Is just assume it means it's time to replace the oxygen sensor, but what is the 'A' and 'B' all about?

And also, I looked at the local auto parts stores and they have the Bosch plug which is $70-$100. I almost shit a brick. Is there any advantage to shelling out this extra money for the Bosch plug? Or is a cheap OEM replacement smarter? And if someone has one for sale feel free to PM me. BTW it's for a 90 LX.

And and one last thing! Since the LX/DX and the EX ask for a different plug (I read because they are in different locations..) would that cause confusion for people who swapped in an A6 ECU? I did the A6 intake swap and also put in an A6 ECU, and haven't had any problems so far, but if the EX has sensors in different locations and such, could it cause the A6 to report incorrectly when installed in an LX/DX?

Thanks for inquiring!

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illegal bump anyone have a sensor for sale, anybody know anything about a CEL code 2?

[wed3k]

not sure how to answer your question but make sure you damn well match part numbers when buying the o2 sensor...im lucky i got the right one off ebay.

no problems so far (bosch replacemnt and costed me about 50) but trying thr get it off under the car (EX) was a bitch.

[green5thgen]

If needed I have an O2 sensor that goes right before the flex tube that is in good working order. I will sell it to anyone who needs it.

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I'm gonna bump my old thread here, I forgot about that code 2 from a while back but I wanted to know what the differences between all the different oxygen sensors are?

36531-PK3-A05 SENSOR, OXYGEN $165.28
36531-PT2-J02 SENSOR, OXYGEN $165.28
36531-PT3-A12 SENSOR, OXYGEN $180.05

From what I can tell, the last one is for the f22a1 engine, using the shorter cord, located for the manifold bung.

The first 2 are shown when you choose the f22a4 or a6 engine, but what are the differences? And which should I buy? I have an a1 but with many a6 parts.

Does anyone know?

[Caution]

it shouldnt matter, they all do the same crap for obd1 and obdO, now when you get to obd2 a or b, then you need to get the right one!

[v4lu3s]

i am pretty sure a code 2 is for cars that have 2 o2 sensors.....

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Well my car sure as heck never had 2 sensors, but it did throw that code way back when.

As far as the sensors go, I know why the a1 and a6 need to be different because the cables are different lengths. But I just wonder why they have 2 choices for the a4/a6 O2 sensor. I want to get the right one, and I don't know which to choose. Perhaps I should just flip a coin.

[cp[mike]]

doesnt matter which ECU and intake manifold you have. the A1 (with the 4-1 header) had the sensor on the front of the header, so thats where the plug was on the harness. A4/A6 (and any prelude - anything with an OEM 4-2-1 header) had the sensor just before the flexpipe behind the oil pan. they both go to the same pins on the ECU. the only difference is that they used the opposite end plug, one had a female end, one had male (forget which is which atm). i guess honda did this because both sensors had different lengths of wire?

and i would assume that its the same sensor thats showing up under those 2 different part numbers, since the A4 and A6 were two distinctly different header designs with THEIR own part numbers. also, their prices are the same...

as far as youre concerned, if youre still using your original A1 header with the o2 sensor up front, buy the one for the A1.

if you ever install a header with the o2 bung behind the oil pan, youll need to extend the harness. if you just relocate/extend it and reuse your original plug, you would need to use an A1 sensor in the new location, because it would have the correct gender end to match your harness plug.

im also wondering how you got a code 2, since yes thats for cars that had 2 sensors. which no OBD1 cb7 ever did...

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I have an aftermarket header, so I planned to get the a4/a6 sensor. I'm on my third 02 sensor in the past year, but they've all been bosch, and I now I want OEM.

I didn't know that about the connectors though, do you suppose all three O2 sensors send info back the same, or rather, all three are the same except for the plug?

[cp[mike]]

I have an aftermarket header, so I planned to get the a4/a6 sensor. I'm on my third 02 sensor in the past year, but they've all been bosch, and I now I want OEM.

well thats not very encouraging. i figured id try my luck with the bosch one i guess ill see how soon it dies...

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Well mine haven't died, but they act like ass....its like they report the wrong info to the ecu, and the engine revs up and down over and over. Whenever I try to be cheap and not buy OEM, I get let down.