Toyota: check engine light, o2 sensors, dirty fuel

Question
I have a 98 Tacoma and the check engine light just went on. It has 48000 miles and is in great shape....any ideas??

Answer
Hi Jason,

There are many many sensors located all over the fuel, intake, engine, and exhaust systems.  Any one of them can cause the Check Engine Light to come on.

Some common things to check:  

Make sure the gas cap is tightened 3 clicks.  Improper fuel tank pressure can cause the CE light.

Dirty fuel injectors, even tho it runs good.  Try a bottle of fuel injector cleaner run through a tank of gas.

O2 sensors could be going out early.  Normally they need replacement at around 60K miles.

You can reset the light by pulling the EFI fuse under the hood, and reinserting it. (this is basically resetting the ECU, same as unhooking the battery, without having to reset all the other stuff like your radio buttons, alarm system, etc.)  If you have an automatic transmission, your ECU will have to start over relearning your driving habits so your gas mileage may suffer for a month or so.  But the CE light may stay off.  If the light comes back on, you need to have it diagnosed by someone with a Toyota code reader.  Most AutoZone, CarPort, etc. parts places will diagnose for a small fee.

Good luck!
SherryB