Posted by MrGutWrench on December 21, 2001 at 18:25:01:

In Reply to: Check engine light came on at exactly 50000 miles posted by Mike on December 21, 2001 at 10:12:54:

A lot of people don't understand that there are TWO lights on the speedo readout cluster --
1) "Check Engine" comes on whenever the engine management computer senses a problem. It could be low fuel pressure, an electrical problem like a broken wire to a temperature sensor on the engine, a bad Ox sensor, or an evaporative leak (this last is why a loose fuel cap will cause it to come on).
2) "Service Engine" comes on at specific mileages. It's a reminder that maintenance on the emissions control system is needed. This is NOT an oil change, etc. -- it's service that is specifically needed on emissions equipment like catalysts or Ox sensors. You DON'T have to have a dealer do it -- most of it most owners can do, but not doing it can cause serious problems to your vehicle. You'll need a shop with an OBDII compatible test machine to read any codes and switch off the lights but any competent shop will have one of these. You can do most of the work yourself and have the shop finish off the electronic part of the service.
Some people will tell you "just turn that Service Engine light off" -- that's stupid as a box of rocks. You MIGHT get by skipping the emissions maintenance but it's far too big a gamble to be smart.
Good luck, MrGutWrench (mrgutwrench@atTEA.net - To email, change "atTEA" to "att")