Shifter assembly showing the lever in park.
Hence shifter has front contact switches that t
ells the BCM that the BCM is in park when the lever is all the way forward. To see if the lever contact switch needs to be adjusted, then just push the lever hard forward when you try to start the car, and if this starts the car, then will need to adjust the micro switch lever.
The second one is that you have to have your foot on the brake pedal, pushing it down.
Tech II or OBDII scanner will make short work of this, since you can go into BCM data to make sure that the brake pedal sensor is working correctly, if not, then do a BPS relearn if the U of the switch has worn instead.
Hence, Brake pedal switch is not a on/off type switch, but a resistance switch that are not the same from switch to switch. So car needs to first lean the pedal not touched resistance, then pedal pressed down resistance next.
To see if the pedal needs a relearn or replacement with relearn, push the lower side of the starter button for 5 seconds to get the car into run mode/motor off, press the brake pedal down the normal amount that you are when starting the car and have someone see if the brake lights are coming on.
Hence if dials are sweeping, then BCM does have the car in run mode to start with (why you can jump the relay and car starts), but waiting on the Brake pedal push with trans in park conformation. Before it going to send the signal for the relay to spin the starter.
And yes, if you replace the brake pedal sensor, will need to do a BPS relearn of the sensor to the car. The pedal untouched is easy to program in since you don't touch it, while when you do the pedal press to program that in, only press the pedal enough to just lightly get into the brakes, since you're not going to be two footing the pedal to start the car.
As for the run crank relay on the BCM, it's on the bottom side of the module with the back-up lights relay if the tech II is both showing that the trans is in park, and the brake is being pushed enough for the BCM, but the relay is still not firing.