my check engine light came on the day before yesterday and so I used the on off on off on trick to get the codes and now i have 3, can anyone tell me what they are I got 12, 21, and 55. Didnt know I had so many problems until now, If anyone can tell me what these mean it will really help, thanks,

21 means something is wrong with your o2 sensors. i have no idea what the other 2 are.

ok, heres the link to check your pcm codes http://www.2gnt.com/nuke/modules.php?name=Sections&op=viewarticle&artid=8
but ill go ahead and tell you. the 12 means power to the PCM has been disconected in the last 50 keyturs, no biggie at all. 21 means something is messed up with your heated 02 sensor, check your wires and harness. 55 means end of trouble codes/no codes found. the only one is 21 and just check your wires. have you changed your o2 plugs?? maybe the wiring is messed up. hope this helps

12 means that your battery was disconnected within the last 50 key-on cycles. Translation: it means nothing. 55 is the code to signal that the list of codes is done.

Check it out: http://www.2gnt.com/www/files/pcmcode.htm

Whew good stuff so i know why the O2 sensor one is on, lol cuz uhh I got a catback exhaust that didnt have a hole for it so its kinda jus rigged up under my car, ? though, why did it take so long to come on i mean ive had it not not hooked up for a long time, also I havent disconnected my battery in a long time so any other reason that one came on? thanks,

i'm not sure why it took so long to come on but it happens to me all the time. i'll do something that should turn it on but it doesn't. then a couple weeks or months later it pops on.

Yea the CEL will come on and off for no reason.

OK while were on the subject my 02 sensor has just been kinda kickin it under my car, how sturdy do u think it is, also do u think that it being exposed to rain and all will have any effect on it?

Screw that sensor. As long as it's not broken you can solder a resistor inline and you'll get rid of the CEL. http://www2.cesa12.k12.wi.us/brent/personal/neon/pic/cat_resistor.html

If you break it - you'll have to get a fake o2 sensor like I did.


ride__________95 Eclipse RS : 5 speed
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