CEL light for a cat...possibly?

[cincycats51]

Well i bought my 99 eclipse last year and on the ride home from getting in 300+ miles away the CEL came on...i ran the test when i got home and it read it was a cat problem. first option was to replace the 2nd o2 sensor...didnt work. so instead, not knowing what i was doing i got a high flow cat...obviously keeping th CEL light on. seeing that the light was on before that im sure there was another problem. i took it to the local mechanic and they said it COULD be wiring inside the other side of the o2 sensor that they couldnt fix...figures...so somehow i got the CEL light to turn off for 3 days to get inspection and i know it being on i lose performance but it doesnt bother me. now its time for the inspection again, and its still on. i was thinking o2 simulator which 1. i cant find one, and dont know how to make one, and 2. they may not even be the problem seeing the CEL light was on BEFORE i replaced the cat. im so lost and dont have alot of money to spend to fix it. what to do!?

 

[crimsondragon]

You can start by posting what's the code number it's throwing instead of second guessing what it could be.

 

[cincycats51]

You can start by posting what's the code number it's throwing instead of second guessing what it could be.

im sorry...the code was P0420 which is catalytic efficiency below threshold bank 1...and thats what i was told to do is replace the o2 sensor first seeing as that was the cheapest fix

 

[crimsondragon]

Did you reset the ECU after every modification? I'm thinking you did but it seems like you barely know how you managed to keep the CEL off for 3 days.

 

[PRJTstealth]

did you turn off the cel for those 3 days or was it just some luck that turned it off temp.

 

[cincycats51]

did you turn off the cel for those 3 days or was it just some luck that turned it off temp.

well the cel light went off after first failed inspection...they just reset everything for me and said hey give me your 30 bucks for failed inspection...so i drove it around 300 miles and it never came back on, ran the test and nothing failed, put it in for inspection the next day, it passed, stayed off for maybe another 200 miles then came right back on. so everything was reset after the mods...it must have been luck eh?

 

[crimsondragon]

So you're saying it went off and then came on again. Did you check the code for the lastest CEL or did you just assume it was P0420?

 

[cincycats51]

So you're saying it went off and then came on again. Did you check the code for the lastest CEL or did you just assume it was P0420?

i did just assume it was P0420...just from the fact that no other code came up when i ran the test and got that...

 

[crimsondragon]

I think it's a fluke. Disconnect your battery for a minute then put it back on. It should reset the ECU.

 

[cincycats51]

I think it's a fluke. Disconnect your battery for a minute then put it back on. It should reset the ECU.

ill do that tomorrow and drive it for awhile and let you know if it comes back on...

So the CEL light came back on...and came back in under 100 miles which even surprised me...i thought it was supposed to be like 200 or more...hmmm what to do...