Dinnyin

So, had a CEL when I went in for my last oil change (no, I don't do it myself, yes, I take it to my dealer, but I know the service rep there).

Came up "bad secondary oxygen sensor." At the dealer, those things are like $300 + install.

So, I took a member's advice and went the cheap route. Bought a "Denso OE identical O2 sensor" from SparkPlugs.com. Dropped by a mechanic (I don't have a lift or stands) and paid $50 to have it put in.

$60 sensor + $50 install, I'm ahead by like $250.

Except, the friggin light came right back on! The mechanic doesn't give a ratsass; I just paid him to put a part I supplied on to fix a problem he didn't diagnose. Sparkplugs.com isn't going to take the sensor back once instaleld but, maybe I can replace it under warranty if it turns out to be defective.

Now what? Back to the dealer to pay for further diagnosis? I have no way of knowing if the new sensor is bad, if it wasn't speced right for the car, or if there's something else altogether wrong...

advice appreciated

thanks

dinnyin

LostMotion

Highly unlikely that first would go bad randomly and the second would go bad in a matter of days. Must be something else causing it.

Dinnyin

not days, instantly. as soon as started the car after the install and resetting the light, it came right back on.


what else could it be?

s2kapow

I'm assuming 'secondary' means the downstream sensor, after the cat. If that's the case, maybe your upstream sensor is bad? As I understand it, all OBDII ECUs compare the readings from the upstream and downstream sensors to determine whether or not the cat is functioning properly. So maybe your upstream sensor is sending a bad signal, and the signal from the downstream sensor is out of the acceptable range based on the upstream signal. Seems like you should get an error code related to the upstream sensor if this was the case, but I still think it could be the upstream sensor. They seem to die first since they're exposed to non-catalyzed exhaust.

Of course, like you said, maybe it's more simple and the sensor you bought is damaged or is out of spec for your car.

Maybe this is a dumb question too, but did you pull the error code after making the replacement to confirm it's the same one? If not, maybe you now have a different code / problem? Hope this helps -- good luck

CKit

Make sure you ordered the right part (secondary O2 sensor) and that he put it in the right place (cat converter).

The sensor is fine. Pull the code. There's a chance your cat is toasted, leading to the O2 sensor dying in the first place.

Dinnyin

not a dumb question, I don't have a code puller, so no, I can't confirm it's the same error code. I suppose that's a possibility.

I'm sure I ordered the right part (according to SparkPlugs.com sensor matching scheme) and put it in the right place.

dead cat huh? is that bad? ($$)

MikeyCB

Nah not $$ if you just replace it with a test pipe!!

Or go get a high flow cat for MUCH cheaper than stock and have the flanges welded on to have it bolt up to the existing parts of your exhaust.

iam7head

are those the solder tail sensor or it's pigtail(like oem)

the cheaper soldering required sensor are know for throwing heat circuit code.

it's everyone's guess right now, go to autozone and have the code pulled.

Dinnyin

just like OEM, didn't have to solder anything, just pluged in

going by autozone after work

Sideways

Did you reset the ECU to get rid of the light?