Besides being annoying, what does the CEL do?

Regarding the thread title, it's the other way around - the malfunctioning system elicits the CEL. In other words, a rock in your shoe is not caused by a limp; the rock causes the limp.

The CEL need not be illuminated to retrieve the code. The computer stores the codes. So pull that puppy and see what it is. Some codes do cause the vehicle to run in FMEM and others do not.

Good luck.

- The mere existence of CELs makes me wish I owned a <1992 car (prior to OBD-I) or <1997 (prior to OBD-II). Okay rant time.

- CA requires smog tests only on cars more than 5 years old. We've had CELs come on with many cars (Volvo, Miata, Cougar, ML430) but we ignored them and the cars continued to run great for even 60k more miles (with regular maintenance throughout). Then the day of reckoning with the smog test.

- CELs piss me off so badly because CA emissions test facitilities won't even measure the pollutants coming out of your tailpipe...they immediatly fail you and charge you $50 for failing when they see the CEL. Then the repair shop will charge $94 to connect an OBD-II code reader (for 10 seconds of work), then they'll charge hundreds of dollars to resolve whatever minor issue exists.

- So I bought an OBD-II code reader on eBay in an attempt to circumvent the $94 charge and simply tell the mechanic what code needed to be resolved. No dice...they had to use their own OBD-II code reader; then they called me and confirmed the same code and still charged me $94 (for 10 seconds labor) and $335 for some @#$%ing module. (all on a car that has always ran smoothly and efficiently, oil changes every 4k miles, MANY new parts, etc).

- I honestly wish Congress would lessen regulations on emmissions testing (afterall modern cars put out virtually zero pollutants in comparison to the <1970's gas hogs). But, instead..Congress seems intent on their Henny Penny hysteria about the sky falling with doomsday global warming they claim will be resolved if everyone drives hybrids (which still have internal combustion engines) or even worse - Al Gore golf carts. No, we should focus more on reducing/combatting forest fires (which are much more harmful to the environment than the tens of millions of ultra low emmissions vehicle (ULEV) Camrys/Corollas and Accords/Civics clogging our nation's highways).