From the `98 Ford Service CD -
"The MIL is illuminated for all emissions related electrical component malfunctions. For malfunctions attributable to a mechanical component (such as a clutch, gear, band, valve, etc.), some transmissions are capable of not commanding the mechanically failed component and providing the remaining maximum functionality (functionality is reassessed on each power up)- in such case a non-MIL Diagnostic Trouble Code (DTC) will be stored and, if so equipped, a Transmission Control Indicator Light (TCIL) will flash."
What this basically means, is that the CEL will illuminate, and stay that way, during an emmissions related electrical component faliure or malfunction. That is until the PCM memory is either cleared manually or the fault is not detected after two consecutive drive cycles.
If there is a mechanical failure, in the tranny, it will cause the TCIL (O/D light) to flash, which means that the PCM has stored a code indicating which fault it was. But!! This code will be cleared once the engine is turned off.
So. If your O/D light flashed, there was a code there to be read. If you turned your engine off before you could actually read that code, that code would disappear. If when you started your car again and the CEL was not on or the O/D light did not flash, there is nothing there to read. You will have to wait until the fault happens again.
Hince the mass confusion that we have all had over this issue.
