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Home >> Ford >> 2012 >> Mustang Base, 2D Coupe, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 43 (Starting System - Gasoline Engines -- F250-F550 Super Duty) >> Diagnosis And Testing >> Starting System >> Pinpoint Tests >> Pinpoint Test A: The Engine Does Not Crank >> Normal Operation

Normal Operation

WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

When the ignition switch is turned to the START position, the PCM receives a starter motor request signal. Voltage is then supplied to the starter relay from the PCM. The PCM receives a signal from the digital Transmission Range (TR) sensor that the vehicle is in PARK or NEUTRAL (vehicles equipped with an automatic transmission) or from the Clutch Pedal Position (CPP) switch when the clutch pedal is fully depressed (vehicles equipped with manual transmission). A ground is supplied from the PCM causing the starter relay coil to energize and the relay contacts to close. This allows voltage to be supplied from Battery Junction Box (BJB) fuse 89 (40A) to the relay contacts, which then flows to the starter solenoid. The solenoid is grounded at the starter motor. Energizing the starter solenoid engages the starter drive into the ring gear and closes the solenoid contacts allowing voltage directly from the battery to the starter motor to start the engine. The PCM will disengage the starter motor based on engine running (rpm threshold), a set crank time has been exceeded or the ignition switch has been turned to the OFF position.

This pinpoint test is intended to diagnose the following:

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