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Home >> Ford >> 2012 >> Mustang Base, 2D Coupe, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 44 (Starting System - Diesel 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 is turned to the START position and released, the PCM receives a starter motor request signal. Power 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. A ground is supplied from the PCM causing the starter relay coil to energize and the relay contacts to close. This allows power 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 power directly from the battery to the starter motor to start the engine. The PCM disengages the starter motor based on engine running (rpm threshold), a set crank time has been exceeded or the ignition has been turned to the OFF position.

This pinpoint test is intended to diagnose the following:

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