I've been battling an issue w/ the CEL in my 03 Taco. During my 5 week adventure dealing with repairs to exhaust/muffler, front CAT,and front O2 sensor the damn thing keeps popping up. Every time it comes on I go back to the mech. he runs the systems check and now says system passed- no codes. But yet after 50-60 miles it comes on again. Go back, the mech. runs it again, no codes- mind you every time he connects the comp. the light goes off. I had a rear O2 sensor replace about a year ago and again there are no codes popping up when the CEL comes on. What else can I tell this mech. to check? Is it electrical. I'VE BEEN TRYING TO PASS FOR A STICKER!! I need help boys. Sicerely, Frustrated and Broke Bill

 

So the code turns off whenever he plugs the OBD scantool in? If so just get your own scanner and clear the CEL before you take it for inspection or get a Scangauge II and it will tell you why the light is coming on as soon as it comes on. Just some quick thoughts, I'm sure others will have some advice. Good Luck!

 

I tried to get my truck inspected after the mech. cleared it but the inspector came back telling me my truck couldn't be scanned.

 

how much is a scangauge II?

 

Mind you the CEL came on right 45miles after I had the new exhaust put in.Then was told a p420 code popped up. The mechanic said it was or should be the front CAT. He replaced that, 50 miles later the CEL came on again. Went back and they scanned it finding the front O2 sensor is faulty. He replaced that, drove 60 miles about and CEL came on again. Went back, he scanned it again, comp. says system passed( I actually watched him do this) and no codes or code history. Drove 60 miles the CEL came on again. At this point I already spent 1300$. I'm dumbfounded, the mech.says it could be electrical, orimay need a rear CAT and rear O2 sensor. He checked the rear O2 sensor and it was fine but I guess you can't check the rear CAT except forgiving it a diagnosis.