Normal Operation

When the ignition switch is turned to the START position, the PCM receives a starter motor request signal. Voltage is 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 19 (30A) 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.

• DTC P0512 (Starter Request Circuit) - this DTC sets when the PCM detects an open or short to ground on the starter request circuit.

This pinpoint test is intended to diagnose the following: 

• Anti-theft system
• Fuse
• Battery
• Battery cables
• Wiring, terminals or connectors
• CPP (manual transmission)
• Ignition switch
• PCM
• Starter motor
• Starter motor relay
• Digital TR sensor (automatic transmission)