Another Check engine light question...

[xport]

I see there are a lot of these on the boards! Glad I'm not alone. I have a 2001 Celica. About a year ago, the check engine light came on. I took it to the dealership, they told me I needed a whole new Catalytic Converter. I said I'd think about it; A few days later the light went back off on it's own. For the next 4 mos, the light came on about once a month, stayed on for a few days, then turned back off. I had another diagnostic run (by a seperate mechanic, not the dealership), he read the code and said to replace one of the O2 sensors (not sure which one...he said it there were two, the one we replaced was the easiest to fix). Light turned off for a week...then flickered back on. Had the 100,000 mile tune performed. Light went back off for a month; came back on. It's been flickering again, <off 3 weeks, on 3 days, back off 3 weeks> ever since. The light came on a week ago, this time it didn't go off. Two days ago I found this site, and cleaned the MAF sensor (appeared to be a common problem). It's been two days, the light is still on (although, gas mileage is much better than before..unbelievably better!).

Had a Diagnostic run on it at Autozone today: Code PO420.

Any ideas? do I just need to reset it? If so, how? I'm pulling my hair out, and I know lots of people who have had terrible experiences with the local dealership (no offense to anyone who works at a dealership). Any help would be greatly appreciated.

[mustang67408]

Originally Posted by xport

I see there are a lot of these on the boards! Glad I'm not alone. I have a 2001 Celica. About a year ago, the check engine light came on. I took it to the dealership, they told me I needed a whole new Catalytic Converter. I said I'd think about it; A few days later the light went back off on it's own. For the next 4 mos, the light came on about once a month, stayed on for a few days, then turned back off. I had another diagnostic run (by a seperate mechanic, not the dealership), he read the code and said to replace one of the O2 sensors (not sure which one...he said it there were two, the one we replaced was the easiest to fix). Light turned off for a week...then flickered back on. Had the 100,000 mile tune performed. Light went back off for a month; came back on. It's been flickering again, <off 3 weeks, on 3 days, back off 3 weeks> ever since. The light came on a week ago, this time it didn't go off. Two days ago I found this site, and cleaned the MAF sensor (appeared to be a common problem). It's been two days, the light is still on (although, gas mileage is much better than before..unbelievably better!).

Had a Diagnostic run on it at Autozone today: Code PO420.

Any ideas? do I just need to reset it? If so, how? I'm pulling my hair out, and I know lots of people who have had terrible experiences with the local dealership (no offense to anyone who works at a dealership). Any help would be greatly appreciated.

P0420 means the cat converter is deteriorating and not performing up to the standards set.
YOU NEED A NEW CAT CONVERTER.

[xport]

Thanks Mustang. Another question; is this something that would be best done at the dealership? Or should I try to find the part online and take it to a local mechanic? It's a pretty expensive part, so I don't want to take it to someone who might do more harm than good...if that makes sense. And it ain't easy for a single girl to find a good mechanic in these parts!

[mustang67408]

Originally Posted by xport

Thanks Mustang. Another question; is this something that would be best done at the dealership? Or should I try to find the part online and take it to a local mechanic? It's a pretty expensive part, so I don't want to take it to someone who might do more harm than good...if that makes sense. And it ain't easy for a single girl to find a good mechanic in these parts!

That part is 8yr/80K miles WARRANTY.

I am BIASED, I prefer a dealership.
Some people like them ,some dont
It all depends on the people working there at the dealership.

If you want to do it your self, the vehicle has to be in the air.
PM sent

[PtRickGTS]

Originally Posted by xport

I see there are a lot of these on the boards! Glad I'm not alone. I have a 2001 Celica. About a year ago, the check engine light came on. I took it to the dealership, they told me I needed a whole new Catalytic Converter. I said I'd think about it; A few days later the light went back off on it's own. For the next 4 mos, the light came on about once a month, stayed on for a few days, then turned back off. I had another diagnostic run (by a seperate mechanic, not the dealership), he read the code and said to replace one of the O2 sensors (not sure which one...he said it there were two, the one we replaced was the easiest to fix). Light turned off for a week...then flickered back on. Had the 100,000 mile tune performed. Light went back off for a month; came back on. It's been flickering again, <off 3 weeks, on 3 days, back off 3 weeks> ever since. The light came on a week ago, this time it didn't go off. Two days ago I found this site, and cleaned the MAF sensor (appeared to be a common problem). It's been two days, the light is still on (although, gas mileage is much better than before..unbelievably better!).

Had a Diagnostic run on it at Autozone today: Code PO420.

Any ideas? do I just need to reset it? If so, how? I'm pulling my hair out, and I know lots of people who have had terrible experiences with the local dealership (no offense to anyone who works at a dealership). Any help would be greatly appreciated.

CEL code you got is P0420 Catalyst System Efficiency Below Threshold (Bank 1) I think you may have a bad catalyctic converter or a bad 02 sensor in that CConverter. I had a friend who had similar problem as yours, he replaced his MAF sensor, catalyctic converter and O2 sensor. Keep me posted if you need more help. Definitely go to a local dealer, if you still underwarranty, it should cover it.

Pat

[Tennesseestorm]

Strange.... the T100 I test drove today also had the check engine light illuminated.