Nissan Repair: Check Engine Light, nissan sentra, needle in a haystack

Question
Hi! I have a 1994 Nissan Sentra with 112,000 miles and I have to smog it. The only problem is my check engine came on about a month ago. I haven't noticed any bogging or rough idle; in fact, the car is running as good as ever. I went to Autozone to see if I could borrow one of their scanner tools, but apparently it's against the law, now, for them to lend out the scanners (at least here in California). I got my hands on several scanner tools and the connections aren't the same, so I assume they're different. Anyway, I was wondering how I could go about trouble shooting the problem. Any suggestions?

Thanks,
Eric

Answer
Hi Eric -

There are literally hundreds of sensors and modules that illuminate the CEL (Check Engine Light). Without the OBD, it is a needle in a haystack to diagnose. The popular ones are O2 sensor, camshaft sensor, and cat converter, however you do not want to just arbitrarily change those out, as it gets costly.

What I normally tell my clients is to reset the light by either removing the fuse off the computer, or disconnecting the battery for a few minutes. If the light comes back, you have a "hard code" and should be checked.

I agree with you in the sense that the car runs just a great as it was ever. Sometimes these CEL lights stay on for a long time and shuts off and it is not necessarily and indication that the car is needs profound work.

Hope this helps -
aloha
calvin