Check engine light question.

[john88jr]

Hello,

Having an issue with my Check Engine light, it keeps coming on, I go to the dealer and they reset it and send me home telling me that there are no codes being pulled?

So what could be causing the check engine light to come on if it isn't producing any codes?

1999 Explorer. 145k miles.

.

[FNA]

Bad "Check Engine" light connection, but that should give a code.

[dfordski]

I believe the C.E. light occurs when attempts by the ECM to make adjustments to attain the 14.7:1 air/ fuel ratio it demands has failed repeatedly. Even if the ECM croaks it's mentioned in the Continuous Memory. The C.M. Errors are displayed after the K.O.E.R. test completes unless the Tech resets the ECM before the C.M. begins to display (their is a little lag time). Techs unfamiliar w/ OBD ll sometimes don't realize the test's not over till the fat lady sings (referring to the Continuous Memory Error Codes Displayment) and prematurely reset. Back to square one. I'd try another dealer. The scan Reader will denote when in C.M. mode and even a clean test results in a code (111) at completion. No "ifs", "ands" or "Butthead Techs"! Does it run like it has the Flu while the C.E. light is on? Here's a "WTF" on OBD's info link. Prior, present and future abilities (as in when the C.E light informs you there's a problem, it will also drop a Dime on you to your local "Smog Police" via electronic transmission. GPS integration is not mentioned but.....not much more of a stretch. "Smart Bomb" deployment would seem the next logical step, but initially limited to California. NOTE: Unless underlined, contents of post was accurate & reliable. Anyway, here's the link I mentioned: NationMaster - Encyclopedia: On Board Diagnostics