For ECM programmers
Gotta question for anyone who programs ECMs or has a working knowledge of ECMs. I'm wondering what the effects are to the engine's control module programming when CEL is triggered. As an example, the ECM uses the signals from the pre-cat 02 sensors to regulate fuel delivery by way of adjusting the pulses of the injectors. If the sensor(s) are slow to respond, a code goes "pending". If this occurs more than once in 40 drive cycles, the code matures and triggers a p0133 or p0153. When that happens, what does the ECM do about regulating the fuel delivery? Does it do a "best guess" estimate for the AFR, or is there another source that backs up the 02 sensors?
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