Principles of Operation: Notes

WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

The starting system is electronically controlled by the PCM. The PCM receives the following inputs:

Transmission in PARK or NEUTRAL, from the digital Transmission Range (TR) sensor (located in the automatic transmission)
CPP Switch input (with manual transmission)
Correctly coded ignition key, from the Passive Anti-Theft System (PATS), vehicles equipped with PATS
Ignition switch request to start the engine
BJB Run/start relay voltage

When the ignition switch is placed in the START position, voltage is supplied to the Body Control Module (BCM) internal logic. A starter motor request signal is also sent to the PCM. If the PCM recognizes the correct input signals, it provides the starter relay coil with both voltage and ground. The starter relay contacts close, providing voltage to the starter solenoid, allowing the starter motor to activate. The starter motor continues to crank until the ignition key is released from the START position.

Vehicles equipped with an automatic transmission have a digital TR sensor. The digital TR sensor prevents operation of the starter motor unless the transmission is in NEUTRAL or PARK.

Manual transmission equipped vehicles have a CPP switch. The CPP switch prevents operation of the starter motor unless the clutch pedal is fully pressed.