Correct, on the 94 and later for certain, the PCM looks for certain inputs.... You could have cold started your car and headed for the highway, as soon as you turn the ignition on the O2 sensor heats up, you start the car and very shortly thereafter the O2 is already giving the PCM a good signal... Say you are a block from the highway... You pull out and get up to 44-45mph and eventhough the engine is still cold, you'll hit TCC lock with the O2 data and correct Vehicle speed conditions are met... Once you get to 55-60 you will have the TCC locked even with a cold engine...
On the older cars 87-91, 92 and possibly 93 as this was a mixed year for the none heated O2 and heated O2... These cars will look for about 150F before the PCM will apply the TCC..
This small change was able to improve emissions and fuel economy... Every little bit counts
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