Installed My New Oxygen Sensor And Now The Check Engine Light Is On! Help!!!

[panamacolin]

HI,

Wondering if anyone can help just installed a brand new o2 sensor on my 1995 vx. Its a NTK OEM sensor. The car seems to run fine just the light is on. I have checked the connection and its good. I unplugged the battery and reconnected it...still check engine light. Is there anyway to reset the ECU?

Thanks!
Colin

[omgwtfbyobbq]

Should be a fuse for the ECU that needs to be pulled for a certain amount of time. You can do the same thing w/ the batt, but it's more of a pain...

[thisisntjared]

um... what code is it throwing?? is it the o2 sensor code or the o2 sensor heater? or something else entirely?

if it is an o2 code then it is likely the wiring elsewhere in the car. is everything in the wiring harness factory?

[jadziasman]

You really need to find out what the code is. Did you try putting the old LAF sensor back in to see if the CEL goes out? I once had the misfortune of buying a counterfeit L1H1 from Autozone.com and had exactly the same problem you described. Luckily, I was able to return it for a full refund. Hopefully you will be able to do the same if you can't get this one to work. If the check engine light stays on after a restart that means your ECU is running in the fail safe mode. This means the ECU is essentially ignoring input from the LAF sensor and is using a ROM program instead. This can't be good for mpg.

[panamacolin]

Jadziasman,
Just installed the old one and no check engine light. I bought the new sensor on ebay im going to do my best to return it.

The canadian dood bought from the same people and no problem...wonder what the deal is..

What do you suggest i do?

[thisisntjared]

so wait, you bought a new sensor for fun and the new sensor throws the CEL. now why did you buy the new sensor again?

[jadziasman]

All you can do is inform the seller the part was defective and ask for a refund or replacement.

I still have the old LAF sensor in the engine 11 months after the CEL went on and have had no problems. My average has been 44 to 46 mpg with the two VX's I've driven for 12 years. I haven't replaced an LAF sensor yet.

I will be sure to replace the sensor when the CEL comes on and stays on.

Maybe you should do the same and leave the one you have in there as long as you're still getting good mpg and the CEL stays off. Easy for me because Michigan doesn't run emission tests yet. But when I was in Illinois - we got tested every two years and the eighth year test results were no different from the second year results - really low emissions.

[panamacolin]

thought it would up my mileage to swap it out and the price was right...90bucks...plus just trying to get all routine maintenance out of the way...

[jadziasman]

90 bucks seems to be the selling price of bogus LAF sensors. Autozone.com was selling theirs at 89.95 originally which was a great deal. Lately though Autozone.com is selling the NTK L1H1 sensor for over $300 so they definitely got the wrong ones before and they were in Bosch packaging no less. I should have known because the wire colors didn't match the OEM sensor (there ain't no blue wire on the L1H1). The counterfeit might have been an NTK L2H2 knock off.

With all the issues with Chinese goods out there today I wouldn't be surprised if what I had was a Chinese knock off. There are some car companies in China making copies of the Smart ForTwo and the '08 xB. The new xB counterfeit looks like it could share parts with the real one!

[thisisntjared]

man those chinese will rob you BLIND! their trade laws are crap!