The check engine light came on the truck 3 weeks ago. I figured that some rust proofing oil might have gotten on the outer part of the O2 sensor,so I cleaned it up and reset the ECU by pulling the neg battery cable. Everything was fine until yesterday when the CEL came on again. I have new plugs and I cleaned the MAF and TB last month weeks before the light even came on. I am positive that it's my O2 sensors as the HC reading was high (under limit though) when the emissions test was done. Anyhoo, I picked up a USB OBD2 scanner today but I can't find the damn port. I checked everywhere under the dash, both driver and passenger side and under the seats. Apparently I have an SR5 but it appears to be a base model (paper work says SR5) - I am not sure they had the OBD2 port on the base model (I thought they were required by law on 96 and up models). BTW I did check under the driver side dash by the center console - it ain't there. Do I have to remove the dash panel to access it? Please help me find it! Thanks

 

Well I dont know if the 4runner is different, but my 99 taco SR5 is under the dash by my right knee. You really cant miss it. And yes, it was required. So unless someone yanked out the port, its there somewhere.

 

Under the dash towards the center console.

 

This is a '98 4Runner