O2 Sensor Replacement

[howellru]

I just bought my first Explorer ('96 4.0L) which has a the check engine light glowing bright red. The shop wants $190 to replace the upstreaming O2 sensor. To me, the job seems fairly easy. Am I being niave?

Will someone please walk me through the O2 sensor replacementt process, step by step? Also how do I reset the computer once the new sensor is in?

Thanks.

hru out.

 

[Alec]

It is easy if you can get to the sensor itself. I had headers on my 96 so the sensors were very easy to get to. Your stock manifolds may prove it more difficult. Basically though, if you can get to the sensor you can easily replace it. Unplug it and thread it out, replace and you're done. Resetting the computer: disco the negative battery terminal and turn your headlights on to drain any residual current. 10-15 mins later button everything back up and let the truck idle with all accessories off and all hands off (no pedal or steering input) for about 10 minutes, the next time (or few times) you drive it try to go for more than 20 minutes and drive it a bit hard.

 

[aldive]

Replacing an O2 sensor can be a very difficult task due to siezing of the threads.

How do you know that the O2 sensor is bad? Did you scan it?

 

[howellru]

Thanks for the quick response, guys.

Aldive, the shop ran a diagnostic check and the computer code P0133 (check slow O2 response) came back. Is that what you're calling "scanning the sensor? Is there anything I can use to help break any seized threads (i.e. WD-40)?

Alec, my rig is bone stock; no after market headers. What will I have to work through to get to the sensor? Do I really have to do all you mentioned to reset the computer? Can't just disconnect the battery for half hour? Wonder if Auto Zone would reset it for free?

These and other reasons are why I was hoping for a step by step process.

Thanks again. Keep the post coming.

hru out.

 

[twomedicine]

O2 & Computer

I don't see how anyone could be more specific than Alec's instructions. Maybe you'd want to get underneath and take a peek at where the sensor is located before purchasing your replacement to see if you are confident about its replacement. At worst, if you get stuck, you can always drive it to the repair shop you were already involved /

Also, the computer relearning process as described is very important and it would be to your best advantage to do it right the first time. Your owner's manual has it spelled out too. Putting on the lights is a good idea and I'll make note of that advice since that's not in the manual, but that would assure a complete discharge and a clean slate, so to speak, for the auto-programming