Quoted:
Quoted: For starters, a Service Engine Soon light and a Check Engine light are the same thing.
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Not Always ..... The Check Engine Light (CEL) is mandated by federal law (OBD-II) and is Yellow in color , it can only be illuminated by emission spacific codes , Anything exceeding 1.5 times the FTP ( Federal Test Procedure ) emission test results for that model/engine combo .
Service Engine Soon (SES) is Manfacture opption and is Red in color and can be illuminated by anything they want .
Or thats the way the original SAE J1979 guideline was written .
The problem is that between 1996 and 2000 many manfactures were using one or the other or even both sometimes while sorting out their complience to SAE J1979 standard (OBD-II). After 2000 it was adjusted to include both SES & CEL , just so long as its a Yellow/Amber light ,and only iluminated by Emission related failures .
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Sorry, but you are totally off base. SAE J1979 does not mandate anything about colors of lights. J1979 defines the diganostic test modes, Mode $01 through Mode $09. I perform calibration work within the parameters of J1979 every day.
The terms CEL and SES are not even SAE terms. Look at SAE J1930...the correct term is MIL, Malfunction Indicator Lamp. The other terms were manufacturer assigned, and it became confusing because the MIL for one model could be called an SES, and another model might use the term SES for an indicator that service, such as an oil change, was needed.
The MIL is not only used for emission related trouble codes. SAE J2012 mandates the different Diagnostic Trouble Codes (DTCs) P0, P1, P2, P3, C0, C1, C2, C3, B0, B1, B2, B3. P-powertrain, c-chassis, B-body.
If you want a copy of any of the SAE standards, I can send you a copy.