I got a Service Engine Soon Light on and I thought I fixed the problem, but all I did was unhooked the battery to clear the computer out after I fixed it, but the light came back on. My question is is unhooking the battery good enough to clear the codes or do I need to take it somewhere and have it hooked up to a computer to clear the codes.

 

Leave it unhooked for a few minutes. 10-30 minutes should do it. I would do that and then take it to a auto parts store and have them read the codes again. I have had several codes at once.

 

ECM BAT,(93Z) , fuse on driver side panel for 30 seconds and you dont lose radio station/etc.......


If the SES light comes back on, there is still a problem....

 

Yes.... 30 seconds is all you need. No need to disconnect the battery, and no reason to leave it unhooked for 10-30 minutes.

The PCM BAT fuse is in the end-of-the-dash panel on some years, and in the under hood box on others. Since you didn't tell us anything about your car, no one can give you a detailed answer. Might want to add a "signature" with basic info about your car - year, model, tranny, any major mods. Increases your chances of getting an accurate answer.

If you fix the problem, the light should go off without "resetting". The code will remain stored for a period of time, but will not affect anything.

 

Thanks guys for the info I will try it again. Car is a 97 z28 with basic bolt ons: TB, cold air kit, pulleys. etc and a 175 shot of nitrous. BTW, code keeps being 420 "bad cataytic converter".

 

take it to autozone. do it right...no resetting stations or driver's memory programming in the PCM.

and you'll actually know whats wrong with it.

 

I wish it was that simple because it isnt. Last year same thing, said bad converter. I replaced the converter and it still said bad converter. It ended up being a wire came loose from the MAS.

 

Why don't you spend the $40 at Harbor Freight for an OBD-II code reader? Then look the codes up on this list (OBD-II tab at bottom of page):

http://shbox.com/1/Dtcs.htm

or here......

http://service.gm.com/gmspo/mode6/

 

P0420 Three Way Catalytic Converter (TWC) system low efficiency Bank 1

...doesn't mean "bad converter". It could even be the O2 sensor.