'98 Civic HX CEL - O2 sensor

[cems70]

Hello all,

I previously posted about my '98 HX poor FE: http://www.gassavers.org/showthread.php?t=9419

The general consensus was the primary O2 sensor was bad, so I bought direct fit replacement: WALKER Part # 25025001, which listed the 92 -95 VX and 92 - 01 HX as valid vehicles for this part number. I replaced the sensor yesterday (correct plug, no splicing anything), and the CEL came on w/ the primary O2 sensor code (61) after 10 miles. I figured I should have reset the ECU, so I disconnected the negative battery cable, waited a couple of minutes, and reconnected it. The CEL came on again about 50 miles later.

Any suggestions about what the problem is? Should I have bought the genuine Honda O2 sensor? There was no CEL before replacing this except a few times in the last couple of years as described in the thread mentioned above. Any suggestions is appreciated.

[reallyslow]

disconnecting the battery will not reset the ecu. the car is obd2 it has too be resetted with a scan tool.

[want2buyVX]

Check the exhaust manifold for hair-line cracks, this is a well know problem with 1996-2000 Civics and will definetly set off the CEL.

[cems70]

** Update **

Found out from the auto parts store where I purchased the Walker O2 sensor that they had a bad batch of these with 80% of them returned. Not sure if it was only this specific Walker part number or all Walkers. I returned it for a full refund and purchased a $99 unit that someone recommended on another thread. No CEL.

Reallyslow: I've posted many times (and seen other posts) about resetting the HX ecu by disconnecting the negative battery cable and no one has ever mentioned that a scan tool is necessary to do this. Can anyone else verify this? Do I need to reset the ecu after installing the new O2 sensor 6 weeks ago, or does the ecu adapt to the new O2 sensor on its own?

[want2buyVX]

You must use the scan tool to clear the code.

If you install a new O2 sensor, you will still have the CEL when you turn the car on.

I found this out with my 98 Civic EX.