Starter Motor Request (SMR) Circuit
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2019 Lincoln Navigator, 2019 Lincoln Nautilus, 2019 Lincoln MKZ, 2019 Lincoln MKT, and 2019 Lincoln MKC. However, it is still accessible from the selected car via links, so may be relevant.
The SMR circuit provides the PCM with a signal from the ignition switch to the PCM. The input is pulled high when the ignition is in the START position and the transmission range (TR) sensor ignition lockout circuit allows the starter to engage.