I have a 01 Tacoma Prerunner V6 auto and the check eng light came on ,the thing runs good and I can't see anything wrong under the hood .I was talking to a buddy and he said disconnect the battery and then reconnect and see if the light is still on .I did this trick and the light was out for about 15 miles and then it came back on ,any ideas? Yes the gas cap is on tight.

 

go to autozone. they will pull the code for free.

 

Disconnecting the battery is just going to reset the system - it doesn't get rid of the problem.

You can try your local supply shop and they may pull it for free but some states don't have it, for example CA, probably because of liability.

Harbor Freight sells a generic code reader that I've used to diagnose my problems and it is pretty reliable. It's about $40-50 may be worth looking into.
http://www.harborfreight.com/cpi/cta...emnumber=46030

OR

You can do a search and find alternate diagnostic tools that will give you way more info than just error codes if you're interested.

 

Tacoma Dude pretty much has you covered in his post.
When you get the code number, post back and we'll help you get it fixed.

 

Or you can go to the dealer.Most codes are emissions related and are covered 8years/80k miles.

 

But if it is not emissions, you get to pony up at least $70 for them to hook up the scanner to the truck.
I wouldn't do it unless you were 100% sure or are willing to pony up the $$$ for them to do it.

 

Went to local mech.and it was the o2 censer so I had that replaced and the light is still on .

 

did they reset the code after replacing the sensor? also if it isnt still fixed, go back there and complain saying you said this much for a bad sensor to cure my lights and i paid, and its still not done.....

 

Just because you get an o2 sensor code doesn't mean the sensor is bad many things can cause this code. Running rich is usually the culprit and that relates to other things. MAF/MAP, IAC, dirty air filter, bad secondary ignition parts. Thats why the diagnosic read out is much better than the codes, unless you like to check everything out!!