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Engine Light (Notorious O2 Sensor)

12 February 2005
I have a 100% stock 2000-T currently with 49,699 miles that I purchased beginning of March this year and just last week the check engine light came on while warming up for a drive. Extremely upset since it only gets to be driven once a week. Today, I took it to AutoZone for a free OBDll scan and the unit pulled up code P0141 (O2 sensor heater circuit malfunction; bank 1 sensor 2).
I have driven the car twice since the light came on and had not noticed any change in performance, i.e idle speed, acceleration, no unusual engine noise. Vehicle essentially runs perfect except for the engine light on. Have read on prime threads about the extended warranty Acura has on emissions related check engine codes- does warranty apply even if I am not the first owner? Also ,would it do any further engine damage if I continue to drive the vehicle with this code classification?
Should I try resetting just to see if engine light would turn on again? (Maybe/Hoping it's a fluke.) It's hard to believe my dreamcar would already have this problem. Thanks for any advice and even more thankful for a great website.

I am the third owner of my '96 NSX, and my Acura dealer had no problem with replacing my front O2 sensor for free under the extended emissions warranty. I drove my car for about 6 months before the bad sensor actually got replaced. I'm not recommending it, but just letting you know my experience.
Having just replaced an O2 sensor yesterday, hopefully I can answer some questions:

It won't hurt the car to drive it with the O2 sensor out - they're used to 1) determine if your catalytic converters are working properly, and 2) supposedly to help the engine fine tune itself better.

The warranty should still cover you. Check with your dealer on this one- they'll be the only people that can tell you absolutely.

You can reset the check engine light and see if it'll come back. I doubt it's a fluke, though.

Lastly, you can replace it yourself. I got my non-oem sensor from www.oxygensensors.com and it was a direct replacement - around $80, although you'll have to wire it up to the existing connector.

After replacing O2's, the biggest difference is usually found in fuel economy improvements.
O2 senors 1 (bank 1 and 2) will effect the car, even in the short term. However, O2 #2 will not. The computer reads the differance between 1 and 2 on any given bank and determines cat con efficiency. The code you have however does not relate specifficaly to the cats, but rather the heater circuit for the O2 sensor which monitors them.
It IS under the federal emmisioms warranty for 7 years/70k miles. You should NOT reset, so that your dealer can verify the code. If I were you, I would take it to the dealer and get it fixed while its still free. Remember, time is calculated from the first in-service date, so if it was sold in late 99, warranty expires next summer. Why wait??

I called Honda America and a local dealer to verify emissions warranty and they both said my NSX year (2000) does not have any extended emissions warranty? Can you please e-mail me with info regarding this 7 year limit?
I was already quoted $360+ dollars installation & labor plus tax. Thanks for your input.

There are two emissions warranties being confused here:

1: 95/97 NSX - Honda has lengthened the emissions warranty to 14 years 150K miles and covers/replaces certain items due to an agreement with the EPA.


2: 8 Year/80 K mile Federal Emissions Warranty - covers ALL OBDII cars, regardless of manufacture. Covers "major emissions components", which are basically the cats and the ECU. Sensors are not covered under this warranty.
Thanks for everybody's input. NSXT, I did found out through EPA's website about the 8 year/80k federal emissions warranty on "major" emissions components and you are right. These include the 1) Cat Converter; 2)ECU and 3) OBD. Unfortunately, the O2 sensors fall under the "emissions related components" and are warranted only for 2yrs/48K under federal law. The manufacturer's warranty on such items are more generous in this regard, 4yrs/50K according to American Honda.
So, I'm stuck with having to foot the bill to get it fixed. Anybody knows which sensor to get (part number) for a P0141 check engine code= O2 sensor heater circuit malfunction; bank 1 sensor 2. I think I can get these cheaper online - quote given me by a local dealer is $302.33 list price. Add labor and tax it's going to be a tad under $400 to get rid of the check engine light :mad:
Again, thanks for everyone's advice and taking the time to share their knowledge and experiences.

If you cut and paste your own, then $52 from oxygensensors.com is a pretty good deal. Otherwise, even from Acura discounters like acuraautomotiveparts.org they're pretty pricey, considering you're paying the difference for a harness and insulators.
My car recently got the Malfunction Indicator Lamp light on, so I guess I have to goto the dealer to see. I have a 1996 Targa, 5 spd. :frown:
Hope it's nothing serious. My OEM sensors are on their way ; $208 from oemacuraparts.com; can't wait to get rid of that irritating check engine light. :smile:
I drove my M3 with the CEL for months.. I cleared it a half dozen times.. In the end I just put new sensors in, and the car was the same as it was beforehand. That stupid CEL though was so annoying, why wait on this kind of thing? Next time I won't, I hope!

favetita said:
Hope it's nothing serious. My OEM sensors are on their way ; $208 from oemacuraparts.com; can't wait to get rid of that irritating check engine light. :smile:

I took the car to my local nsx tech, and he pulled out the codes, he said it's the O2 Sensors. Then he helped me reset the codes. He said, sometimes, it's hard to tell if the 02 Sensors are really defective or not. So after he reset it, the Malfunction Indicator Light doesn't lite up anymore after start up. He said if it comes back on again, I should replace the 02 Sensor. But so far so good, no problem, since. favetita, I was wondering if you tried having them reset the codes? Or did you just have them replace the 02 Sensor right away?