Starting System: Overview — Ford Mustang V рестайлинг 2 (2012-2014)

Principles of Operation

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

Correctly coded ignition key, from the Passive Anti-Theft System (PATS)
Clutch pedal applied, from the Clutch Pedal Position (CPP) switch, vehicles with manual transmission
Transmission in PARK or NEUTRAL, from the digital Transmission Range (TR) sensor, vehicles with automatic transmission
Starter motor request, ignition switch in the START position

When the ignition switch is placed in the START position, 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.

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

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

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)

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Scheme 3: PINPOINT TEST A: THE ENGINE DOES NOT CRANK

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A1 CHECK THE BATTERY Check the battery condition and charge. Refer to «BATTERY, MOUNTING AND CABLES»(ref-574143) . Is the battery OK? Yes : GO to A2. No : CHARGE or INSTALL a new battery. REFER to «BATTERY, MOUNTING AND CABLES»(ref-574143) . TEST the system for normal operation.
A2 CHECK THE PCM FOR DTCs Using the DTCs retrieved in Inspection and Verification, check for Passive Anti-Theft System (PATS) and PCM DTCs. Were any PCM DTCs retrieved? Yes : If DTC P0512 is retrieved, GO to A14 . If PCM DTC P1260 is retrieved, REFER to «ANTI-THEFT - PASSIVE ANTI-THEFT SYSTEM (PATS)»(ref-574181) . All other PCM DTCs, REFER to «ELECTRONIC ENGINE CONTROLS»(ref-574141) . No : For automatic transmissions, GO to A3. For manual transmissions, GO to A4 .
A3 CHECK THE PCM TR SENSOR PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. While observing the TR PID, place the vehicle in PARK and then NEUTRAL. Does the PID match the gear selection? Yes : GO to A5 . No : REFER to «AUTOMATIC TRANSAXLE/TRANSMISSION - 6R80»(ref-574115) , to diagnose the TR sensor.
A4 CHECK THE PCM CLUTCH PEDAL AT OR NEAR BOTTOM OF TRAVEL (CPP_ BOT) PID Enter the following diagnostic mode on the scan tool: DataLogger - PCM. While observing the CPP_ BOT PID, fully disengage the clutch. Does the PID change from NO to YES? Yes : GO to A5. No : GO to A18 .
A5 CHECK THE PCM STARTER MOTOR RELAY ENABLE (STRT_RLY) PID NOTE: For manual transmission, fully disengage the clutch Monitor the STRT_RLY PID while holding the key in the START position. Does the PID change from DISABLED to ENABLED? Yes : GO to A6. No : GO to A16 .
A6 CHECK THE STARTER MOTOR RELAY Swap the starter relay with a known good relay and attempt to crank the engine. Does the engine crank? Yes : INSTALL a new starter relay. TEST the system for normal operation. No : GO to A7.
A7 CHECK THE VOLTAGE TO THE STARTER MOTOR RELAY Ignition OFF. Disconnect: Starter Motor Relay. Measure the voltage between Battery Junction Box (BJB) starter relay socket, pin 30, circuit SBB19 (BU/RD), harness side and ground. Is the voltage greater than 10 volts? Yes : GO to A8. No : VERIFY BJB fuse 19 (30A) is OK. If OK, REPAIR circuit SBB19 (BU/RD) for an open. TEST the system for normal operation. If not OK, REFER to the «SYSTEM WIRING DIAGRAMS»(ref-541407) to identify the possible causes of the circuit short.
A8 CHECK THE STARTER MOTOR Connect one end of a fused jumper wire to BJB starter relay socket, pin 30, circuit SBB19 (BU/RD) and momentarily connect the other end of the fused jumper wire to BJB starter relay socket, pin 87, circuit CDC25 (BN/GN). Did the starter motor engage and the engine crank? Yes : GO to A14 . No : GO to A9.
A9 CHECK THE BATTERY GROUND CABLE Measure the voltage between the positive battery post and the battery ground cable connection at the engine. Is the voltage greater than 10 volts? Yes : GO to A10. No : INSTALL a new battery ground cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-574143) . TEST the system for normal operation.
A10 CHECK THE STARTER MOTOR GROUND Measure the voltage between the positive battery post and the starter motor case. Is the voltage greater than 10 volts? Yes : GO to A11. No : CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
A11 CHECK THE VOLTAGE TO THE STARTER MOTOR Measure the voltage between starter motor C197A, circuit SDC02 (RD) and ground. Is the voltage greater than 10 volts? Yes : GO to A12. No : INSTALL a new positive battery cable. REFER to «BATTERY, MOUNTING AND CABLES»(ref-574143) . TEST the system for normal operation.
A12 CHECK THE STARTER MOTOR Connect one end of a fused jumper wire to starter motor solenoid 197A, circuit SDC02 (RD) and momentarily connect the other end of the fused jumper wire to starter motor solenoid C197B, circuit CDC25 (BN/GN). Did the starter motor engage and the engine crank? Yes : GO to A13. No : INSTALL a new starter motor. REFER to «STARTER MOTOR - 3.7L»(ref-574163-S16055914442013082300000) or «STARTER MOTOR - 5.0L (4V)»(ref-574163-S30350586992013082300000) or «STARTER MOTOR - 5.8L (4V)»(ref-574163-S41569967852013082300000) . TEST the system for normal operation.
A13 CHECK FOR START INPUT AT THE STARTER Connect: Starter Motor Relay. Disconnect: Starter Solenoid C197B. Measure the voltage between the starter motor solenoid C197B-1, circuit CDC25 (BN/GN) and ground, while holding the key in the START position. Is the voltage reading greater than 10 volts? Yes : CLEAN the starter motor solenoid S-terminal and connector. CHECK the wiring and the starter motor for a loose or intermittent connection. TEST the system for normal operation. No : REPAIR circuit CDC25 (BN/GN) for an open. TEST the system for normal operation.
A14 CHECK THE PCM START CIRCUITS FOR A SHORT TO GROUND Disconnect: Starter Motor Relay (if not previously disconnected). Disconnect: PCM Connector C175B or C1381B. Measure the resistance between PCM C175B or C1381B, harness side and ground, using the following chart. PCM Connector Circuit 5.0L and 5.8L , C175B-7 3.7L , C1381B-7 CDC12 (YE) 5.0L and 5.8L , C175B-37 3.7L , C1381B-37 CDC54 (WH/GN) Are the resistances greater than 10, 000 ohms? Yes : GO to A15. No : REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
A15 CHECK THE PCM START CIRCUITS FOR AN OPEN Measure the resistance between PCM C175B or C1381B, harness side and the BJB starter relay socket, using the following chart. PCM Connector Circuit BJB 5.0L and 5.8L , C175B-7 3.7L , C1381B-7 CDC12 (YE) BJB starter relay socket, pin 85 5.0L and 5.8L , C175B-37 3.7L , C1381B-37 CDC54 (WH/GN) BJB starter relay socket, pin 86 Are the resistances less than 5 ohms? Yes : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-574141) . TEST the system for normal operation. No : REPAIR the affected circuit for an open. TEST the system for normal operation.
A16 CHECK THE START CIRCUIT FOR VOLTAGE AT THE PCM Disconnect: PCM C175B or C1381B. Measure the voltage: For 5.0L and 5.8L , between PCM C175B-16, circuit CDC35 (BU/WH) and ground, while holding the key in the START position. For 3.7L , between PCM C1381B-16, circuit CDC35 (BU/WH) and ground, while holding the key in the START position. Is the voltage greater than 10 volts? Yes : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-574141) . TEST the system for normal operation. No : GO to A17.
A17 CHECK THE IGNITION SWITCH Carry out the Ignition Switch Component Test. Refer to appropriate OEM WIRING COMPONENT TESTING for component testing for component testing. Did the ignition switch pass the component test? Yes : REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation. No : INSTALL a new ignition switch. REFER to «STEERING COLUMN SWITCHES»(ref-574137) . TEST the system for normal operation.
A18 CHECK THE BOTTOM OF TRAVEL CIRCUIT FOR AN OPEN Ignition OFF. Disconnect: CPP Switch C257. Disconnect: PCM C175T or C1381T. For 5.0L and 5.8L , measure the resistance between CPP switch C257-1, circuit CE903 (BU/OG), harness side and PCM C175T-19, circuit CE903 (BU/OG), harness side. For 3.7L , measure the resistance between CPP switch C257-1, circuit CE903 (BU/OG), harness side and PCM C1381T-26, circuit CE903 (BU/OG), harness side. Is the resistance less than 5 ohms? Yes : GO to A19. No : REPAIR circuit CE903 (BU/OG) for an open. TEST the system for normal operation.
A19 CHECK THE CPP GROUND CIRCUIT FOR AN OPEN Measure the resistance between CPP switch C257-2, circuit GD129 (BK/YE), harness side and ground. Is the resistance less than 5 ohms? Yes : GO to A20. No : REPAIR circuit GD129 (BK/YE) for an open. TEST the system for normal operation.
A20 CHECK THE CPP SWITCH Connect: CPP Switch C257. For 5.0L and 5.8L , measure the resistance between PCM C175T-19, circuit CE903 (BU/OG), harness side and ground while depressing the clutch pedal. For 3.7L , measure the resistance between PCM C1381T-26, circuit CE903 (BU/OG), harness side and ground while depressing the clutch pedal. Is the resistance less than 5 ohms? Yes : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-574141) . TEST the system for normal operation. No : INSTALL a new CPP switch. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-574141) . TEST the system for normal operation.

Correct starter operation relies on correct mounting of the starter to the engine, alignment of the starter ring gear to the flywheel or flexplate and correct functioning of the starter assembly (internal gears, bearings).