CEL , SES, MIL , NAG Mileage  lamp, INDEX Page     or how to read my DTC's,  my trouble codes           

Check engine , service engine soon, or the  USA only, Federal only, NAG lamp. (NAG =  a.k.a. Mileage warning lamp)   Some call it just the CHECK light.
USA coverage for E03/E33 markets,  (see how to identify cars by its body TAG or VIN) 
If your VIN or Chassis tags show vehicle is Non USA Federal body or a California car, then read the GLOWING pages, only below.
( Non USA cars and Canada market cars do not have the NAG feature, but for sure some Canadians do in fact own and drive many USA cars.    a real E28 markett Canada car have a tag ,like this.
If your Brake and or Over Drive light is glowing wrongly or oddly , hit the Home button above.

DTC's are diagnostic trouble codes, that is, errors the ECU wishes to communicate to the Driver.  This is the whole point of this page, finding those errors. or warnings...
If the CEL refuses to flash code 12 (or other DTC trouble codes) then the NAG switch needs ACTION. (the NAG feature can kill the CEL DTCs features , slide the switch 1 time, or remove it)
I call it a NAG (SES or the Federal mileage Switch is the official name, but  is a timer or mileage based light and is just a dumb NAG function and of no use or intelligence today, it was for leaded fuel long gone now.)

The Nag feature shares the CEL lamp, that is a problem.... to sort out...
89'-95' "NAG" lamp resetting on all USA  Federal Sidekicks and Trackers . (never Calif. or other country cars.)

Paper clip cars:OBD1:
89'-95' CEL LAMP GLOWING ?  (running) and it's not the FED48  NAG  feature above?

Scan tool only cars: OBD2:
96' "USA ,and newer cars, the  CEL LAMP GLOWING? (running)

IF the CEL never glows at KEY ON?

See all  IDIOT lamps, for all cars made.  One page,  An amazing list of these crazy lamps. My favorite, is the man on fire symobol.

If your car is a California car ,then avoid the NAG link above,  how do I tell if car is Calif ?, easy , look at the smog sticker under the hood, (look up; not down) see vacuum map, see California mentioned?

Some Canadians have 4 different cars,  USA Fed, USA Calif, Canada real, and gray market (JDM) ,read your body tags to learn what you have.

NO JDM SUPPORT , I can not read Japanese FSMs., sorry. "Gomen nasai  , Domo Arigato"  !

Cars made after 1995 in the USA are OBD2 compliant, but not so in other countries. Some do not comply ever or do so as a superset of USA OBD2 , EU in 2001 !

rev 2    11-17-2012 added EPA stickers.